Agarwood, the resinous product of Aquilaria spp. (Thymelaeaceae), is highly valued for medicinal and fragrant purposes. Unsustainable forest harvesting contributes to the declining population in the wild, threatening their existence. As a protection effort, cultivation occurred in range countries, mainly in Asia, effectively establishing mass plantations. The success of domesticating Aquilaria relies heavily on technological advancement in agarwood induction, without which the entire thriving industry will collapse. In this paper, we describe efforts since 1929 and current progress and variation in induction as practiced in Asia. The methods include traditional practices and artificial induction via inoculum and chemical inducer, experimented and patented or otherwise. Artificial induction methods are being developed to intensify agarwood production in terms of yield and quality. While traditional methods are commonly applied by rural planters, artificial methods with the use of specific agents/chemicals are seen as more appealing for inducing agarwood, and have a higher demand from entrepreneurs and plantation owners. Several issues related to induction technology faced by stakeholders in agarwood cultivation are presented, such as safety levels, cost, yields, and quality. We conclude by highlighting remaining challenges in induction methods and their associated technologies.

Environmental change attracts particular attention by biologists concerned with the performance of biological systems under stress. To investigate these, dose–response relationships should be clarified. It was previously assumed that the fundamental nature of biological dose–responses follows a linear model, either with no threshold or with a threshold below which no effects are expected to occur in biological endpoints. However, substantial literature, including widespread documentation in plants, has revealed that hormesis commonly occurs. Hormesis is highly generalized and can be utilized as a quantitative measure of biological plasticity. Conditioning induced by adaptive responses also occurs in the framework of hormesis and is of particular importance to environmental change biology with regards to evolutionary adaptations. This paper presents additional evidence for hormetic dose responses induced by temperature in plants. The current understanding on hormesis provides a perspective for next generation environmental change research. Hormesis should have a central role in environmental change biology of vegetation.

The CO₂ released from respiring cells in woody tissues of trees can contribute to one of three fluxes: efflux to the atmosphere (E _A), internal xylem sap transport flux (F _T), and storage flux (∆S). Adding those fluxes together provides an estimate of actual stem respiration (R _S).We know that the relative proportion of CO₂ in those fluxes varies greatly among tree species, but we do not yet have a clear understanding of the causes for this variation. One possible explanation is that species differ in stem radial CO₂ conductance (g _c). A high g _c would favor the E _A pathway and a low g _c would favor the F _T pathway. However, g _c has only been measured once in situ and only in a single tree species. We measured g _c using two methods in stems of Fraxinus mandshurica Rupr. (ash) and Betula platyphylla Suk. (birch) trees in situ, along with R _S, E _A, F _T and ∆S. Stem radial CO₂ conductance was substantially greater in ash trees than in birch trees. Corresponding to that finding, in ash trees over 24 h, E _A constituted the entire flux of respired CO₂, and F _T was negative, indicating that additional CO₂, probably transported from the root system via the xylem, was also diffusing into the atmosphere. In ash trees, F _T was negative over the entire 24 h, and this study represents the first time that has been reported. The addition of xylem-transported CO₂ to E _A caused E _A to be 9% higher than the actual R _S over the diel measurement period. Birch trees, which had lower g _c, also had a more commonly seen pattern, with E _A accounting for about 80% of the CO₂ released from local cell respiration and F _T accounting for the remainder. The inorganic carbon concentration in xylem sap was also lower in ash trees than in birch trees: 2.7 versus 5.3 mmol L⁻¹, respectively. Our results indicate that stem CO₂ conductance could be a very useful measurement to help explain differences among species in the proportion of respired CO₂that remains in the xylem or diffuses into the atmosphere.

Based on reports that variables related to photosynthesis (net assimilatory ratio and chloroplast pigments) are more plastic than the morphological and biochemical variables in a climax tropical species, Cariniana estrellensis, under contrasting irradiance, we hypothesised that plasticity of gas exchange variables is higher in relation to growth, biochemical and anatomical variables. Plants that were 14 months old were subjected to 200 up to 2000 µmol m⁻² s⁻¹ of photo synthetically active radiation (PAR) for 140 days. Growth increased up to 1400 µmol m⁻² s⁻¹ PAR and then decreased at 2000 µmol m⁻² s⁻¹ PAR (full sunlight). This was related to the rate of photosynthesis (A) which showed the same tendency as photosystem II performance index (PI_ABS). The greater thickness of the secondary xylem at 1400 µmol m⁻² s⁻¹ PAR indicated a higher water conductance capacity. The decrease in specific leaf area, elongation of mesophyll cells, and increase in stomatal density observed at higher irradiances were associated with higher leaf fructose and sucrose concentrations. We concluded that the better growth in partial shade was due to higher photosynthetic capacity. On the other hand, photosynthesis was inhibited equally in full sun and deep shade. The high adjustment capacity of C. estrellensis to wide amplitudes of irradiance was provided by greater plasticity of gas exchange variables in relation to growth, anatomical, and biochemical variables.

In this study, in situ investigation was conducted on Chinese chastetree (Vitex negundo var. heterophylla) and spine jujube (Ziziphus jujuba var. spinosa) during early, developed, and closing succession stages. Monthly data were recorded for foliar δ ¹³ C values and foliar N, P, and K concentrations from May to October. Foliar δ ¹³ C values declined with time and differences by succession stage varied by species. Older spine jujube displayed higher foliar N concentration while foliar P concentration was inversely related with N. Chinese chastetree had lower foliar K concentration than spine jujube. Foliar C/N ratio declined during the dry season and increased in the wet season. Foliar N/P ratio increased during the dry season and declined to its initial level until October, when it increased again. Foliar δ ¹³ C value was positively correlated with foliar N concentration. Foliar P and K concentrations were positively correlated to each other. In conclusion, the two shrubs had contrasting strategies of water use efficiency during their succession, but water use efficiency of both species was promoted by N availability and limited by P availability.

This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla × Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed on the seedlings at weekly intervals. Water stress was induced by suspending irrigation until the soil reached 30% available water and water was then replaced so that it returned to field capacity. Gas exchange and leaf water status were measured after 50 days. The experiment was set up in a 4 × 2 factorial randomized block design in four distinct environments: (1) temperatures less than 21.2 °C and vapor pressure deficit of 0.15 kPa; (2) intermediate temperatures of 24.2 °C and vapor pressure deficit of 0.69 kPa; (3) high temperatures of 27.0 °C and high vapor pressure deficit of 1.4 kPa; and, (4) high temperature of 27.0 °C and vapor pressure deficit below 1.10 kPa. Two leaf sun protector treatments were used, with five replications each. High atmospheric demand acted as a stress factor for the seedlings during the initial growth phase. Applications of leaf sunscreen protector provided beneficial effects in maintaining optimum water status and gas exchanges of the plants under water stress.

In vitro conditions of the culture media, plant growth regulators and culture containers may cause anatomical and physiological changes that have negative effects on rooting and ex vitro acclimatization of somatic plantlets. The control of these factors could contribute to the improvement of somatic embryogenesis systems in conifers, especially in pines. The influence of macronutrient concentrations, explant type and culture containers in Pinus radiata D. Don in vitro somatic embryo rooting were analyzed. The highest rooting percentage was observed using half-strength macronutrient concentrations, complete micronutrients and vitamins of Quoirin and Lepoivre medium. Although the use of glass culture vessels was the best to increase the efficiency of the somatic embryogenesis process in terms of rooting, the use of ventilated containers resulted in a significant increase in the percentage of plants able to be planted in the field.

Vegetative propagation is widely used as a means of genotype preservation in clone banks and seed orchards but despite this, the possibility of vegetative propagation using hormones is not clear for many indigenous tree species, including Balanites aegyptiaca. This research is on the vegetative propagation of B. aegyptiaca as influenced by rooting media and growth hormones. Juvenile stem cuttings were obtained from 4 months old seedlings. Nodal stem cuttings 4–5 cm long from 3–5 mm diameter stems were treated with indole-3-butyric acid or indole-3-acetic acid at 50, 100 and 150 mg/L and sown in three different rooting media: top soil, river sand, and sawdust. The results reveal a significant effect (p < 0.05) of rooting media and growth hormones on B. aegyptiaca cuttings. B. aegyptiaca can be propagated vegitatively without the use of hormones. The control was recommended for vegetative propagation of B. aegyptiaca.

Juniperus thurifera L. is an endemic Cupressaceae from the Aurès Mountains of north eastern Algeria and endangered, in part, due to the scarcity of viable seeds. It is threatened by other abiotic factors and the lack of an effective management strategy will increase its risk of extinction. The dearth of information on its in vitro regeneration impedes its application in forest management programs. We therefore developed a micropropagation protocol using microcuttings with auxiliary buds. Cuttings were grown on different combinations of media supplemented with plant growth regulators at different concentrations. The highest number of shoots and branches regenerated from original shoots was obtained on Woody Plant Medium (WPM) supplemented with 6-benzylaminopurine (BAP) (0.5 mg L⁻¹) and 2,4-dichlorophenoxyacetic acid (2,4-D) (0.25 mg L⁻¹). The best elongation of shoots was achieved with WPM supplemented with 0.5 mg L⁻¹ of BAP and 0.25 or 1 mg L⁻¹ of 2,4-D. On the second subculture, shoots had a higher number of branches than those of the first. The highest rooting rate, 38.8%, was obtained with shoots cultured in ½ Murashige and Skoog (MS) medium supplemented with 5.0 mg L⁻¹ each of indol-3-butyric (IBA) and naphthalene acetic acid (NAA). Similarly, the highest root numbers and lengths were produced on ½ MS medium supplemented with IBA and NAA (5.0 mg L⁻¹ each). During transfer to acclimatization, rates of plant losses of 50% occurred. The second part of the experiment showed that the best shoot callusing was on WPM supplemented with BAP and 2,4-D, with either the combination 0.5 + 0.25 or 0.25 + 0.25 mg L⁻¹. The results of this research provide a starting point for further studies on in vitro regeneration of J. thurifera for the sustainable management of its unique ecosystem in the Mediterranean basin.

Salvadora oleoides Decne. is a pharmaceutically important plant. Owing to poor seed formation, viability and, germination, and to anthropogenic disturbances, this species is on the verge of extinction. A reproducible micropropagation protocol to increase the population through tissue culture has been standardized and the results are reported here. Callus tissues were initiated from young leaves and stem explants. Leaf calluses proliferated with 1.5 mg/L BAP and 0.9 mg/L 2, 4-D with additives and continuous slow proliferation up to 15 weeks on 0.5 mg/L BAP and additives with 200 mg/L activated charcoal. Direct shoot initiation took place from stem node explants after 12 days; 4–5 shoots per node were produced in 30 days. Shoot clumps elongated and grew further on MS media supplemented with 2 mg/L BAP, 0.2 mg/L NAA and additives, which generated 20–23 shoots. The elongated shoots induced tap roots with 4 mg/L NAA and 200 mg/L activated charcoal in 12 days. In vitro raised plants produced secondary roots when transferred to pots containing vermiculite maintained at 28–35 °C. The plantlets successfully acclimatised in pots containing soil in natural conditions.

We studied late-entry commercial thinning effects on growth, yield, and regeneration in a 48-year-old jack pine (Pinus banksiana Lamb.) stand. Applied thinning intensities were 27, 32, and 47% of merchantable basal area (BA) excluding skidding trails. After 15 years, mean diameter at breast height of surviving trees in the 47% BA removal increased by 4.9 cm (25%) compared to the unthinned control. The 47% BA removal also increased gross merchantable volume (GMV) tree⁻¹ by 46% compared to the control. The 27% BA removal had twice as much GMV ha⁻¹ compared to the 47% BA removal after 15 years. Moreover, cumulative GMV ha⁻¹ was much higher in the 27% BA removal than in the unthinned control. The highest thinning intensity produced larger trees on average, while the lowest thinning intensity maximized volume production per hectare. Maintenance of acceptable growing stock throughout the 15-year period in the 27% BA removal could provide other ecosystem functions such as biodiversity enhancement or wildlife habitat by delaying senescence. Regeneration data showed that a shift in species composition occurred in the understory. After 15 years, the understory was dominated by black spruce (Picea mariana (Mill.) B.S.P.), white birch (Betula papyrifera Marsh.), and trembling aspen (Populus tremuloides Michx.). If regenerating jack pine is an objective after final overstory removal, additional efforts will be needed to re-establish this species.

Forest inventories based on remote sensing often interpret stand characteristics for small raster cells instead of traditional stand compartments. This is the case for instance in the Lidar-based and multi-source forest inventories of Finland where the interpretation units are 16 m × 16 m grid cells. Using these cells as simulation units in forest planning would lead to very large planning problems. This difficulty could be alleviated by aggregating the grid cells into larger homogeneous segments before planning calculations. This study developed a cellular automaton (CA) for aggregating grid cells into larger calculation units, which in this study were called stands. The criteria used in stand delineation were the shape and size of the stands, and homogeneity of stand attributes within the stand. The stand attributes were: main site type (upland or peatland forest), site fertility, mean tree diameter, mean tree height and stand basal area. In the CA, each cell was joined to one of its adjacent stands for several iterations, until the cells formed a compact layout of homogeneous stands. The CA had several parameters. Due to high number possible parameter combinations, particle swarm optimization was used to find the optimal set of parameter values. Parameter optimization aimed at minimizing within-stand variation and maximizing between-stand variation in stand attributes. When the CA was optimized without any restrictions for its parameters, the resulting stand delineation consisted of small and irregular stands. A clean layout of larger and compact stands was obtained when the CA parameters were optimized with constrained parameter values and so that the layout was penalized as a function of the number of small stands (< 0.1 ha). However, there was within-stand variation in fertility class due to small-scale variation in the data. The stands delineated by the CA explained 66–87% of variation in stand basal area, mean tree height and mean diameter, and 41–92% of variation in the fertility class of the site. It was concluded that the CA developed in this study is a flexible new tool, which could be immediately used in forest planning.

The present study introduces an exploratory data analysis based on structural indicators with the aim to assess the effect of silvicultural practices on tree stand structure. The study was carried out in three Italian beech forests of different ages with stand structures that originated from dissimilar regeneration and cultivation techniques (Cansiglio, northern Italy, Chiarano, central Italy, and Mongiana, southern Italy). Ten structural indicators were considered when investigating the latent multivariate relationship between stand structure attributes before and after thinning operations by using a multiway factor analysis (MFA). The MFA results identified the older stand at Cansiglio as more homogeneous for cultivation regimes, and more stable to practices when compared with the younger sites (Chiarano and Mongiana). Heterogeneous stands were sensitive to silvicultural practice thus suggesting their possible impact on forest attributes. The proposed approach proved to be an operational tool to evaluate comprehensively the response of forest structure to planned interventions.

We assessed the effect of mulching and tree shelters on the establishment and early growth of zeen oak (Quercus canariensis Willd.) during the first 4 years after planting in Northwestern Tunisia. Five mulch types (Italian Stone Pine (Pinus pinea L.), Lentisk (Pistacia lentiscus L.), and a combination of Italian Stone Pine and Lentisk (organic mulches), gravel (inorganic mulch) and control), and three tree shelter types (non-vented and vented tree shelters, and control) were tested. An increase in the number of internodes occurred under the gravel mulch, while a reduction in survival was found for the lentisk mulch. Tree shelters had no effect on survival, but increased mean height growth and reduced mean diameter growth during the 4 years (excepting a non-significant effect for vented tree shelter at year four). Comparison of the annual shoots and growth units (GU) between sheltered and unsheltered plants according to year of formation revealed two growth phases. In first phase, shoots were totally or partially inside the shelters; mean length of annual shoots and GU were greater for sheltered plants. The second phase was characterized by shoots emerging from shelters; mean length of annual shoots and GU were similar for all plants, with or without tree shelters. Results suggest that the use of tree shelters, particularly vented shelters, could contribute to the improvement of the artificial regeneration of zeen oak. The use of mulching alone or in combination with tree shelters did not improve zeen oak performance in the field.

Changes in land cover have a direct impact on forest ecosystem goods and services. In this study, changes in land cover in Sierra de Juarez–Oaxaca ecosystems were estimated using a consistent processing of Landsat images and OBIA methodology. Additionally, landscape analyses using FRAGSTAT were conducted. In 2014, Sierra de Juarez–Oaxaca was covered by approximately 84% of forests, mainly pine-oak and cloud forests. After extensive deforestation until 2001, this trend was reversed and the forest cover surface area in 2014 was slightly higher than in 1979. The comparison of the landscape structure of the forested and agricultural lands suggests an increase in habitat heterogeneity. However, interspersion and juxtaposition indices, showing the patch shape by patch area and perimeter, were similar throughout the study period (1979–2014). Social and economic drivers can explain this situation: namely, community organization, forest enterprises, payment for ecosystem services programs, and changes of agricultural activity. Communities in the Sierra of Oaxaca have reforested degraded lands, created community forest enterprises, and preserved the forest under conservation schemes like those proposed by the Mexican payment for ecosystem services programs. However, their sustainable management faces internal challenges and has become highly dependent on political and institutional decisions beyond their control.

This study quantifies biomass, aboveground and belowground net productivity, along with additional environmental factors over a 2–3 year period in Barnawapara Sanctuary of Chhattisgarh, India through satellite remote-sensing and GIS techniques. Ten sampling quadrates 20 × 20, 5 × 5 and 1 × 1 m were randomly laid for overstorey (OS), understorey (US) and ground vegetation (GS), respectively. Girth of trees was measured at breast height and collar diameters of shrubs and herbs at 0.1 m height. Biomass was estimated using allometric regression equations and herb biomass by harvesting. Net primary productivity (NPP) was determined by summing biomass increment and litter crop values. Aspect and slope influenced the vegetation types, biomass and NPP in different forests. Standing biomass and NPP varied from 18.6 to 101.5 Mg ha⁻¹ and 5.3 to 12.7 Mg ha⁻¹ a⁻¹, respectively, in different forest types. The highest biomass was found in dense mixed forest, while net production recoded in Teak forests. Both were lowest in degraded mixed forests of different forest types. OS, US and GS contributed 90.4, 8.7 and 0.7%, respectively, for the total mean standing biomass in different forests. This study developed spectral models for the estimation of biomass and NPP using Normalized Difference Vegetation Index and other vegetation indices. The study demonstrated the potential of geospatial tools for estimation of biomass and net productivity of dry tropical forest ecosystem.

Ferritin, a universal intracellular protein, can store large amounts of iron and improve plant resistance to abiotic and biotic stress. In this study, a ferritin gene (TaFer) from Tamarix androssowii Litv. was transferred into Populus tomentosa Carr. cv ‘BJR01’ via Agrobacterium. Six independent transgenic lines were obtained with a tolerance to kanamycin and three were randomly selected for further analysis. The PCR and RT-PCR results indicate that the TaFer gene had been integrated into the poplar genome. The effect of the gene on abiotic stress tolerance was tested, and the results show that transgenic plants improve growth, had higher chlorophyll and lower MDA contents, and higher relative electrical conductivity, fewer changes of SOD and POD activities, higher iron content, higher root ferric reductase activity and lower levels of ROS accumulation and cell death in response to drought, Fe-insufficient or Fe-excess tolerance. These results indicate that the TaFer gene can improve abiotic stress tolerance in transgenic Populus tomentosa.

Chinese fir (Cunninghamia lanceolata) is an excellent fast-growing timber species occurring in southern China and has significant value in the forestry industry. In order to enhance the phosphorus utilization efficiency in Chinese fir, four clones named X6, S3, S39 and FK were used, and low phosphorus (LP) stress experiments were performed to analyze the response of different clones to phosphorus deficiency. According to the results on seedling height, maximum root length, leaf blade aspect ratio, root ratio, malondialdehyde content, acid phosphates activity, proline content, soluble protein level, and chlorophyll a and b levels of the tested clones, compared to the control groups (CK), the phosphorus high efficiency clone X6 was screen out for transcriptome sequencing experiments. De novo RNA-seq was then used to sequence the root transcriptomes of X6 under LP stress and CK, and we then compared the gene expression differences under the two conditions. A total of 3416 SDEGs were obtained by comparing the LP and CK groups, among which 1742 were up-regulated and 1682 were down-regulated. All SDEGs obtained from the LP and CK treated samples were subjected to KEGG annotation and classification. Through classification statistical analysis using WEGO software, 607 SDEGs obtained KEGG pathway annotations, which were related to 206 metabolic pathways. In Chinese fir subjected to LP stress, 53 SDEGs related with phosphorus metabolism, and phosphate uptake and transport were obtained from our transcriptome data. Based on the phosphorus metabolism pathway obtained by KEGG classification, combined with previously report on gene annotation related with phosphorus metabolism, the enzymes encoded by SDEG related with phosphorus metabolism and their expression pattern were mapped onto phosphorus metabolism pathway.

Sapindus mukorossi Gaertn. and S. delavayi Franchet are among the most valuable species in the genus Sapindus for their commercially exploitable plant oils and chemicals. However, few studies have addressed genetic variation and improvement for either species. We evaluated the genetic diversity of germplasm from selected plus trees within a wide region and established the relationship between fruit traits and molecular markers. An association analysis based on inter-simple sequence repeats (ISSRs) provided a genetic basis for studies of fruit traits. A total of 247 loci were detected by scanning 61 trees of S. mukorossi and S. delavayi using 16 ISSR markers. Genetic diversity parameters were estimated for selected superior trees (or germplasm) and S. mukorossi and S. delavayi were categorized into two main groups, as well as into four groups within S. mukorossi. An association analysis between the ISSR markers and 14 fruit traits used the TASSEL MLM model. A genetic structure analysis differentiated S. mukorossi and S. delavayi. Eighteen ISSR loci associated with 13 fruit traits (P < 0.005) were identified, with 13, 1, and 4 loci associated with seed oil production, fruit saponin production, and fruit quality, respectively. Using this information, a core collection was selected with adequate genetic diversity and good seed oil characters. Our results demonstrate the feasibility of effectively estimating fruit trait associations in Sapindus using ISSR markers, and the method is applicable and valuable for select germplasm conservation. The markers obtained in this study are potentially useful for molecular-assisted breeding of Sapindus spp.

Lignocellulosic substrates are a good carbon source and provide rich growth media for a variety of microorganisms which produce industrially important enzymes. Cellulases are a group of hydrolytic enzymes such as filter paperase (FPase), carboxymethyl cellulase (CMCase) and β-glucosidase—responsible for release of sugars in the bioconversion of the lignocellulosic biomass into a variety of value-added products. This study examined cellulase production by a newly isolated Aspergillus unguis on individual lignocellulosic substrates in solid state fermentation (SSF). The maximum peak production of enzymes varied from one substrate to another, however, based on the next best solid support and local availability of groundnut fodder supported maximum enzyme yields compared with other solid supports used in this study. Groundnut fodder supported significant production of FPase (5.9 FPU/g of substrate), CMCase (1.1 U/g of substrate) and β-glucosidase activity (6.5 U/g of substrate) in SSF. Considerable secretion of protein (27.0 mg/g of substrate) on groundnut fodder was recorded. Constant increment of protein content in groundnut fodder due to cultivation of A. unguis is an interesting observation and it has implications for the improvement of nutritive value of groundnut fodder for cattle.

The entomopathogenic fungus Isaria fumosorosea Wize, formerly known as Paecilomyces fumosoroseus is reported as a promising biocontrol agent for controlling subterranean termites, particularly those belonging to the family Rhinotermitidae. In Malaysia, the family Rhinotermitidae includes two species of subterranean termites with extremely high economic importance; namely Coptotermes curvignathus Holmgren, and the Asian Subterranean Termite (Coptotermes gestroi Wasmann). To comprehend the potential control of this soil-dwelling fungus against these subterranean termites in Malaysia, an investigation was carried out by testing the pathogenecity of 11 isolates against these termite species. All isolates showed pathogenic potential against the termite (Mortality rate of C. curvignathus: 84.4%; C. gestroi: 67.3%). Isolate PF49 was the most effective against both species of termites and was further tested for its virulence and mycosis. The LC₅₀ values of PF49 against C. curvignathus and C. gestroi were 7.55 × 10³ and 1.09 × 10² conidia/ml, respectively. The average number of days required to complete the mycosis process in C. curvignathus and C. gestroi were 4.7 and 8 days, respectively. These fungi are believed useful for protecting living trees, plants, wood, wood structures, and other cellulosic materials susceptible to termite infestation and damage.

Windthrow plays a critical role in maintaining species diversity in temperate forests. Do large-scale strong wind events (i.e., tropical cyclones, including hurricanes, typhoons and severe cyclonic storms) increase tree diversity in severely damaged forest areas? Do hurricanes (tropical cyclones that occurs in the Atlantic Ocean and northeastern Pacific Ocean) lead to altered relative abundance of shade-tolerant and shade-intolerant species? Did historic hurricanes alter the succession trajectory of the damaged forests? We used nearly 70-year tree demographic data to assess the effects of two major hurricanes on woody species diversity in Piedmont forests, North Carolina, USA. Species richness (S) and Shannon–Wiener’s diversity index (H′) were used to evaluate the changes in tree diversity. The changes in composition were assessed with Nonmetric Multidimensional Scaling. The pre-hurricane successional phase can strongly influence both the damage severity and subsequent responses. Although there is often an immediate drop in diversity following a hurricane, understory tree diversity quickly increases to levels that exceed those prior to the disturbance. This leads to an increase in diversity in stands that were substantially damaged. Hurricanes significantly decrease the dominance of shade-intolerant canopy species while increasing pre-established, more shade-tolerant species. We conclude that large, and infrequent hurricanes help to maintain local tree diversity, but also accelerate the increase in dominance of understory species such as red maple and beech.

The Pine Barrens in New York State are dominated by pitch pine (Pinus ridgida) and scrub oaks (Quercus ilicifolia and Q. prinoides). With fire suppression over the last 90 years or so, P. rigida regeneration has become sparse, even in areas set aside to preserve this type of vegetation. We evaluated the effects of fire and an alternative disturbance (mechanical removal of vegetation) for increasing P. rigida regeneration in the Albany Pine Bush Preserve in eastern New York State. By comparing cover, diameter and height of P. rigida, Q. ilicifolia, Q. prinoides, and Vaccinium spp. (blueberry) growing on the sites with a known fire history, we documented structural and compositional changes in the vegetation since its establishment. We also compared sites on which Quercus sprouts were controlled through mechanical removal. In the years following a disturbance, height and cover of Q. ilicifolia increased continuously and the species became increasingly competitive. Both the density of P. rigida seedlings and Vaccinium cover decreased significantly as the diameter and height of Quercus increased. Our results confirmed that the dominance by P. rigida could be attributed to periodic fires at intervals of 20–25 years. We conclude that removing Q. ilicifolia can favor P. rigida dominance on the barren without fire by releasing pine seedlings from competition.

In central eastern Korea, there has been a continued effort to sustain pine forests because of their value for wood and mushroom production, as well as for other resources. Through the analysis of previously burned areas, we clarified the effects of fire on vegetation dynamics of pine forests by measuring changes in species composition, population structure, and the growth rates of major tree species. Vegetation analysis was conducted on a series of 100 m² plots established in Korean red pine (Pinus densiflora Siebold. & Zucc.) and Mongolian oak (Quercus mongolica Fisch. Ex Ledeb.) forests situated in three different topographic positions on slopes where fire severity varied. We confirmed that most pine trees will succumb to even a surface fire, whereas oak may be killed following high intensity or infrequent fires but will sprout and become dominant. Complete protection from fire favors other, more shade-tolerant deciduous hardwoods. Different restoration plans apply, based on observed vegetation responses for each topographic zone. Near the ridge top, where pine seed sources are most limited, it may be necessary to restore pine forests by planting and to control competing shrubs and herbs. At the mountain foot, where exotic species and species modified by hybridization have invaded aggressively, restoration that involves the introduction of natural vegetation is required. Mid-slope sites, where pine has been replaced by natural vegetation dominated by Mongolian oak, do not require any form of restorative treatment.

Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change. However, to date, research on ground-surface freezing and thawing indices and their relationship with air indices is limited. Based on daily air and ground-surface temperatures collected from 11 meteorological stations in the source region of the Yellow River, the freezing and thawing indices were calculated, and their spatial distribution and trends were analyzed. The air-freezing index (AFI), air-thawing index (ATI), ground surface-freezing index (GFI), ground surface-thawing index (GTI), air thawing-freezing index ratio (Na) and surface ground thawing-freezing index ratio (Ng) were 1554.64, 1153.93, 1.55, 2484.85, 850.57 °C-days and 3.44, respectively. Altitude affected the spatial distribution of the freezing and thawing indices. As the altitude increased, the freezing indices gradually increased, and the thawing indices and thawing-freezing index ratio decreased. From 1980 to 2014, the AFI and GFI decreased at rates of 8.61 and 11.06 °C-days a⁻¹, the ATI and GTI increased at 9.65 and 14.53 °C-days a⁻¹, and Na and Ng significantly increased at 0.21 and 0.79 decade⁻¹. Changes in the freezing and thawing indices were associated with increases in the air and ground-surface temperatures. The rates of change of the ground surface freezing and thawing indices were faster than the air ones because the rate of increase of the ground-surface temperature was faster than that of the air and the difference between the ground surface and air increased. The change point of the time series of freezing and thawing indices occurred in 2000–2001. After 2000–2001, the AFI and GFI were lower than before the change point, and the changing trend was lower. The ATI, GTI, Na and Ng during 2001–2014 were higher, with faster rates than before. In addition, the annual thawing indices composed a greater proportion of the mean annual air temperature and mean annual ground surface temperature than the annual freezing indices. This study provides the necessary basis for research on and prediction of permafrost changes, especially changes in the depth of the active permafrost layer, climate change, and possible evolution of the ecological environment over the source region of the Yellow River on the Qinghai-Tibet Plateau.

Atmospheric particulate matter (PM2.5) seriously influences air quality. It is considered one of the main environmental triggers for lung and heart diseases. Air pollutants can be adsorbed by forest. In this study we investigated the effect of forest cover on urban PM2.5 concentrations in 12 cities in Heilongjiang Province, China. The forest cover in each city was constant throughout the study period. The average daily concentration of PM2.5 in 12 cities was below 75 μg/m³ during the non-heating period but exceeded this level during heating period. Furthermore, there were more moderate pollution days in six cities. This indicated that forests had the ability to reduce the concentration of PM2.5 but the main cause of air pollution was excessive human interference and artificial heating in winter. We classified the 12 cities according to the average PM2.5 concentrations. The relationship between PM2.5 concentrations and forest cover was obtained by integrating forest cover, land area, heated areas and number of vehicles in cities. Finally, considering the complexity of PM2.5 formation and based on the theory of random forestry, we selected six cities and analyzed their meteorological and air pollutant data. The main factors affecting PM2.5 concentrations were PM10, NO₂, CO and SO₂ in air pollutants while meteorological factors were secondary.

Expert opinions have been used in a variety of fields to identify relevant issues and courses of action. This study surveys experts in forestry and climate change from the Asia–Pacific region to gauge their perspectives on the impacts of climate change and on the challenges faced by forest adaptation in the region, and explores recommendations and initiatives for adapting forests to climate change. There was consensus regarding the impacts of climate change on forest ecosystems and on economic sectors such as agriculture and forestry. Respondents also indicated a lack of public awareness and policy and legislation as challenges to addressing climate change. However, the results indicate differences in opinion between regions on the negative impacts of climate change and in satisfaction with actions taken to address climate change, highlighting the need for locally specific policies and research. The study presents specific recommendations to address issues of most concern, based on subregion and professional affiliation throughout the Asia–Pacific region. The results can be used to improve policy and forest management throughout the region. This research will also provide valuable suggestions on how to apply research findings and management recommendations outside of the AP region. The conclusions should be communicated relative to the level of the research and the target audience, ensuring that scientific findings and management recommendations are effectively communicated to ensure successful implementation of forest adaptation strategies.

In a reserved forest parcel in a virgin eastern Hyrcanian mixed beech forest, 80 ha was surveyed to determine the pit and mound topography, canopy gaps and dead trees. The aim was to investigate the spatial patterns and correlation of pit and mound features with canopy gaps. Seventy-five canopy gaps and 61 pit and mound features were identified. The univariate first order nearest neighbor (R_CE) and bivariate second order test (Ripley’s K) statistic were applied. R_CE statistics highlighted a general aggregation pattern for canopy gaps and pits and mounds, while pits and mounds alone were more clumped. Distances between canopy gaps were 130 m average, whereas distances between pit and mound features and dead trees were 60 and 78 m, respectively. Spatial positive correlation of canopy gaps with pits and mounds were observed with all distances. The result of spatial correlations between canopy gaps with pits and mounds confirmed that windthrows cause micro successions in fallen tree ecosystem-scale correlated with gap phase dynamics in the forest community-scale.

This study evaluated impacts of Coriaria nepalensis Wall. colonization on soil characteristics, vegetation structure and composition, regeneration status and expected future compositional changes, biomass and carbon stock in tree species of a mixed conifer forest of Central Himalaya. Three sites (1 ha each in an old landslide area) differing in Coriaria density (low: 20 individuals ha⁻¹; medium: 120 indiv. ha⁻¹; high: 190 indiv. ha⁻¹) were used to enumerate the tree species. A total of 9 tree species and 2830 individuals were recorded from the three study sites that represented a gradient of Coriaria density. Number of species varied from 3 to 7 and the individuals from 690 to 1270 per site with lowest numbers at low Coriaria density and highest at medium Coriaria density. The number of seedlings increased with increasing Coriaria density, and the sites were unique in their seedling composition, indicating marked temporal dynamics. Site wise regeneration analysis showed that regeneration was poor at the site with low Coriaria density and good at the high-density site where many species emerged as seedlings. These results indicate that the ameliorative effects of Coriaria in terms of soil buildup, and accumulation of nutrients and organic matter helped more species to colonize the area. This facilitative ability of Coriaria can be used to restore degraded forest ecosystems of Indian Central Himalaya.

The Afromontane forests of Ethiopia have been under a serious degradation threat. Assessment of floristic diversity and species composition in Biteyu forest of Gurage mountain chain in the central Ethiopia was conducted to examine the pattern of forest structure. Thirty plots of 30 m × 30 m were used to record the vegetation and environmental data using systematic sampling technique. The local name, plant scientific names, DBH, height, species abundance and percentage canopy cover of plant species were recorded. Shannon diversity index and Sorensen’s coefficients was used for comparison among communities and similar forests in the country. Threats to the forest biodiversity in Biteyu were determined by counting cattle interference and wood stumps as disturbance indicators. Relative Euclidean Distance measures by using Ward’s method (linkage) was applied for cluster analysis. Environmental variables were also recorded in each plot. Woody species population structure, basal area and importance value index were analyzed using spreadsheet programs. Data on species distribution and environmental variables in the forest were analyzed by canonical correspondence analysis. A total of 190 species in 154 genera under 73 families were identified. Twenty species were found to be endemic taxa to the Flora Area. Only three plant community types were identified from the cluster analysis due to the high human influence. The Sorensen’s coefficient showed the resemblance of the Biteyu forest with other Dry Evergreen Afromontane forests in the country. Moreover, altitude and slope strongly affect the species composition and structure of Biteyu forest. Given the high anthropogenic influence, high endemism, high dependence of the local community on the forest resources, forest conservation and restoration measures should be done by stakeholders.

By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a natural Metasequoia glyptostroboides Hu and W.C. Cheng population. We studied 2817 M. glyptostroboides trees over 100 years old and analyzed their growth state by measuring 15 factors from stumpage, site condition, and environmental data. The dimensionality of all factors were reduced using the random forest algorithm, and we classified the remaining factors using the following algorithms: random forest, back-propagation (BP) neural networks, and support vector machine (SVM). The applicability of each sorting algorithm was analyzed. When all the d factors are used for classification and modeling, the model’s overall accuracy, kappa coefficient and test accuracy were 85.5%, 0.739 and 85.8%, respectively. By reducing the dimensionality of the factors using the random forest algorithm, 11 factors most strongly influenced the classifications of the growth state of the Metasequoia population: diameter at breast height, height, crown width, age from stumpage data; longitude, latitude, elevation, slope aspect, gradient and slope position from the site condition data; and the edge of the field from the environmental data. For classifying the Metasequoia population, the random forest algorithm has the highest overall accuracy at 87.2%, which is 3.4 and 2.3% higher than the BP neural networks and SVM algorithms, respectively. The SVM algorithm is superior to the random forest algorithm with respect to classifying the state of mortality. The combination of the random forest and SVM algorithms and their combined information can be used to classify and predict the growth state of this natural M. glyptostroboides population to provide a scientific basis for its effective protection.

Pine processionary moth is one of the most important forest pests in the Mediterranean Basin. There is need to explore its distribution behaviour to undertake effective control and determine the edge effect of its horizontal distribution in the stand. Five trial sites damaged by the insect were selected and traps installed in all trees in the sites. The number of nests and larvae was counted and diameter increment cores were taken. The distance to the edge of the stand revealed that there was no statistical difference in the number of nests and larvae up to 25 m while there was a statistically significant difference (0.5%) at > 25 m. There was a 2-fold difference in the density of nests between 0 and 25 m and > 25 meters, and a 3.8-fold difference in the number of larvae. The effect of pine processionary moth on tree diameter was not significant between trees at the edge of the stand and those in the stand.

Scots pine (Pinus sylvestris L.) panels were modified with glutaraldehyde (GA) to various weight percent gains and subsequently coated with several commercial coatings. The drying rate and adhesion of the coatings on the modified wood were measured; the coated/modified woods were exposed outdoors to analyze how the wood modifications influence the coating deterioration. The results showed that GA modification caused an increase in the drying rate of the waterborne coatings, but had no influence on drying of tested solvent-borne coatings. GA-modification did not change the dry adhesion but reduced the wood strength in a pull-off test. Wet adhesion of waterborne coatings was improved, while that of the solvent-borne coatings tended to be somewhat reduced. During 22 months of outdoor weathering, the coated/modified samples exhibited lower moisture content than the coated/unmodified samples, but GA modification didn’t contribute a substantially synergistic effect with surface coatings on resistance to weathering.

Three processing techniques, split-squaring (SS), V-grooving (VG), and split-edging (SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo (Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time (32.1 min), followed by the SS-method (18.2 min), and the SE-method (17.9 min). However, the VG-method showed the highest recovery (82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method (49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.

Magnolia sieboldii K. Koch seed is characterized with having deep dormancy. The inner molecular regulation mechanism has not been investigated because of the absence of a protocol for total RNA (ribonucleic acid) extraction. The extraction of high-quality RNA is important and can be a limiting factor in plant molecular biology experiments. Sufficient high-quality total RNA is required to elucidate the molecular regulation mechanism of germination. However, M. sieboldii seeds with large amounts of secondary metabolites also contain recalcitrant tissues for RNA isolation. We found two simple and low-cost RNA extraction methods for M. sieboldii seeds by evaluating and selecting eight types of methods and further optimizing these methods. The two methods were not only suitable for extracting M. sieboldii seed RNA but also applicable to RNAs from several other tissues. Total RNA extracted through these approaches was applicable for general molecular biology experiments such as qRT-PCR (quantitative real-time polymerase chain reactions). The protocols also meet the strict harsh requirements for transcriptome sequencing and small RNA sequencing. This study provides a powerful approach for future studies at the transcription level.