Temporal land use/land cover (LULC) change information provides a variety of applications for informed management of land resources. The aim of this study was to detect and predict LULC changes in the Arasbaran region using an integrated Multi-Layer Perceptron Neural Network and Markov Chain analysis. At the first step, multi-temporal Landsat images (1990, 2002 and 2014) were processed using ancillary data and were classified into seven LULC categories of high density forest, low-density forest, agriculture, grassland, barren land, water and urban area. Next, LULC changes were detected for three time profiles, 1990–2002, 2002–2014 and 1990–2014. A 2014 LULC map of the study area was further simulated (for model performance evaluation) applying 1990 and 2002 map layers. In addition, a collection of spatial variables was also used for modeling LULC change processes as driving forces. The actual and simulated 2014 LULC change maps were cross-tabulated and compared to ensure model simulation success and the results indicated an overall accuracy and kappa coefficient of 97.79% and 0.992, respectively. Having the model properly validated, LULC change was predicted up to the year 2025. The results demonstrated that 992 and 1592 ha of high and low-density forests were degraded during 1990–2014, respectively, while 422 ha were added to the extent of residential areas with a growth rate of 17.58 ha per year. The developed model predicted a considerable degradation trend for the forest categories through 2025, accounting for 489 and 531 ha of loss for high and low-density forests, respectively. By way of contrast, residential area and farmland categories will increase up to 211 and 427 ha, respectively. The integrated prediction model and customary area data can be used for practical management efforts by simulating vegetation dynamics and future LULC change trajectories.

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.

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.

One of the greatest threats posed by ongoing climate change may be regarded the drought caused by changes in precipitation distribution. The aim of presented study was to characterize reactions to dry conditions and conditions without drought stress on gross primary production (GPP) and net ecosystem production (NEP) of spruce and beech forests, as these two species dominate within the European continent. Daily courses of GPP and NEP of these two species were evaluated in relation to an expected decrease in CO₂ uptake during dry days. The occurrence of CO₂ uptake hysteresis in daily production was also investigated. Our study was performed at Bílý Kříž (spruce) and Štítná (beech) mountain forest sites during 2010–2012 period. We applied eddy covariance technique for the estimation of carbon fluxes, vapor pressure deficit and precipitation characteristics together with the SoilClim model for the determination of drought conditions, and the inverse of the Penman–Monteith equation to compute canopy conductance. Significant differences were found in response to reduced water supply for both species. Spruce reacts by closing its stomata before noon and maintaining a reduced photosynthetic activity for the rest of the day, while beech keeps its stomata open as long as possible and slightly reduces photosynthetic activity evenly throughout the entire day. In the spruce forest, we found substantial hysteresis in the light response curve of GPP. In the beech forest, the shape of this curve was different: evening values exceeded morning values.

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.

Canadian boreal mixedwood forests are extensive, with large potential for carbon sequestration and storage; thus, knowledge of their carbon stocks at different stand ages is needed to adapt forest management practices to help meet climate-change mitigation goals. Carbon stocks were quantified at three Ontario boreal mixedwood sites. A harvested stand, a juvenile stand replanted with spruce seedlings and a mature stand had total carbon stocks (± SE) of 133 ± 13 at age 2, 130 ± 13 at age 25, and 207 ± 15 Mg C ha⁻¹ at age 81 years. At the clear-cut site, stocks were reduced by about 40% or 90 Mg C ha⁻¹ at harvest. Vegetation held 27, 34 and 62% of stocks, while detritus held 34, 29 and 13% of stocks at age 2, 25 and 81, respectively. Mineral soil carbon stocks averaged 51 Mg C ha⁻¹, and held 38, 37 and 25% of stocks. Aboveground net primary productivity (± SE) in the harvested and juvenile stand was 2.1 ± 0.2 and 3.7 ± 0.3 Mg C ha⁻¹ per annum (p.a.), compared to 2.6 ± 2.5 Mg C ha⁻¹ p.a. in the mature stand. The mature canopies studied had typical boreal mixedwood composition and mean carbon densities of 208 Mg C ha⁻¹, which is above average for managed Canadian boreal forest ecosystems. A comparison of published results from Canadian boreal forest ecosystems showed that carbon stocks in mixedwood stands are typically higher than coniferous stands at all ages, which was also true for stocks in vegetation and detritus. Also, aboveground net primary productivity was typically found to be higher in mixedwood than in coniferous boreal forest stands over a range of ages. Measurements from this study, together with those published from the other boreal forest stands demonstrate the potential for enhanced carbon sequestration through modified forest management practices to take advantage of Canadian boreal mixedwood stand characteristics.

The dynamics of litter nitrogen (N) and phosphorus (P) release could be affected by soil fauna and environmental conditions. The objective of the present study was to investigate the effects of soil fauna on the dynamics of N and P during foliar litter decomposition in three types of ecosystems (i.e., montane forest, ecotone, and dry valley) along an elevation gradient. A field experiment using litterbags with two different mesh sizes (0.04 and 3 mm) was conducted from November 2013 to October 2014. Nitrogen and P release rates in decomposing foliar litter from fir (Abies faxoniana) and birch (Betula albosinensis) in montane forest, oak (Quercus baronii) and cypress (Cupressus chengiana) in ecotone, and cypress and clovershrub (Campylotropis macrocarpa) in dry valley were investigated in the upper reaches of the Yangtze River. Soil fauna strongly affected N and P release across different decomposition periods and ecosystem types. The average release rate of N mediated by soil fauna across the entire year was higher in the dry valley (15.6–37.3%) than in the montane forest (0.5–6.4%) and the ecotone (− 3.7–4.9%). The effects of soil fauna on P release rate were manifest in both the montane forest and the dry valley. Moreover, the impacts of soil fauna can vary substantially among different decomposition periods. Our results indicated that soil fauna can significantly affect N and P release during litter decomposition. The N release rate mediated by fauna was likely to be more sensitive to the effects of plant species (i.e., initial litter chemical traits), while the P release rate mediated by soil fauna might be subject to the effects of local-scale environmental factors (e.g., temperature) to a greater extent.

Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effects on species composition. However, specific studies have rarely been conducted in the degraded karst regions of Southwest China despite the high heterogeneity of karst habitats and past human disturbances. In this study, woody species richness and composition on rocky outcrops on a typical karst hillslope were investigated and compared with those of nearby matrices on shallow and rocky soil. Our results showed that matrix vegetation was more diverse in genera and species than vegetation on rocky outcrops. This might relate to the contrasting substrate features and different disturbance histories of these two habitats. Unlike the significant effect of slope on species richness of the matrix vegetation, rocky outcrops exhibited no significant differences between upper and lower slope positions, largely because their microhabitats were similar in different slope positions. Although the study area has been reforested naturally for about 30 years, woody species of the matrix vegetation were still dominated by pioneer shrub species. Rocky outcrops were dominated by late-successional tree species, which was primarily related to their isolated features and resistance to certain disturbances. Most of these late-successional species were not habitat endemics, indicating the possibility for their encroachment into surrounding the matrix. From this aspect, further studies will be necessary to identify and address the limiting factors for the encroachment of these late-successional species into the surrounding environment.

Pterocarpus santalinus L. f. (Fabaceae; red sanders) is prized for its wood whose colour and fragrance is due to the presence of santalins that have pharmaceutical and industrial uses. Red sanders is listed as an endangered plant species on the IUCN red data list as a result of the exploitation of its wood and essential oil. This review emphasizes the pollination biology, seed germination, vegetative propagation and micropropagation of P. santalinus. Excessive use of P. santalinus has also caused the emergence of various adulterants, so accurate identification is essential.

Pinus patula is a species commonly used for reforestation in Mexico. However, efficient methods for the mass production seedlings are required. Micropropagation particularly by somatic embryogenesis provides an option for the rapid multiplication of high-quality, genetically improved material. This study induces somatic embryogenesis in this species using the thin cell layer (TCL) technique. Two sources of explants (complete immature embryos; lTCL segments from immature embryos) were evaluated. The efficiency of TCL from longitudinal sections [lTCL] and transverse [tTCL] was evaluated. The results show using thin cell layers from immature embryos cultivated in 16 light/8 dark hours achieves induction of somatic embryos. A higher percentage of embryogenic callus was obtained when tTCL segments were used as an explant source. These results produced somatic embryos from tTCL segments of an immature embryo without germinating the seed, making the process more time efficient. In addition, this technique can be used to generate somatic embryogenesis in forest species that have low germination rates.

Although Pinus sibirica and Pinus koraiensis are resistant to cold or low temperatures in the cold temperate regions of the northern hemisphere, the former has a stronger cold resistance. Research has been limited to the comparison of physiological responses of the two species to cold stress. In this study, 5-year-old seedlings of P. sibirica and P. koraiensis were subjected to six temperature treatments, [20 °C (control), 0 °C, − 20 °C, − 40 °C, − 60 °C, and − 80 °C], under different stress periods (6, 12, 24, and 48 h). The results showed that differences in each physiological index were significant between P. sibirica and P. koraiensis, except for the permeability of cell membranes, reactive oxygen species, proline and soluble proteins. An ANOVA test indicated that there were extreme differences among the temperatures for each index, stress time and temperature × time for most indices. All indices showed a similar trend for P. sibirica and P. koraiensis with decreasing temperature or the extension of stress time. Soluble sugars and proline increased at 0 to − 20 °C and then remained unchanged with temperature decline. Other indices showed an increase from 20 to − 20 °C, stable from − 20 to − 40 °C and a decrease from − 40 to − 80 °C. All the indices increased and then declined along with the prolonged cold stress time, except for the control. From 0 to − 40 °C, the permeability of cell membranes, relative conductivity, reactive oxygen species and malonaldehyde of P. koraiensis seedlings were higher than in P. sibirica, but superoxide dismutase, peroxidase, catalase activity and soluble sugars, proline, and soluble proteins content emerged as opposite. This study compared the physiological mechanism responses to cold stress between P. sibirica and P. koraiensis to provide the basis for the introduction, distribution, and genetic improvement of these coniferous species.

Soil organic carbon (SOC) mineralization is closely related to carbon source or sink of terrestrial ecosystem. Natural stands of Larix olgensis on the Jincang forest farm, Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10, > 10–20, > 20–40 and > 40–60 cm. The results showed that compared with a mid-aged forest, the SOC stock in the young forest was 32% higher. Potentially mineralizable soil carbon (C ₀) in the young forest was 1.1–2.5 g kg⁻¹, accounting for 5.5–8.1% of total SOC during the 105 days incubation period and 0.3–1.5 g kg⁻¹ in the mid-aged forest at different soil depths, occupying 2.8–3.4% of total SOC. There was a significant difference in C ₀ among the soil depths. The dynamics of the SOC mineralization was a good fit to a three-pool (labile, intermediate and stable) carbon decomposition kinetic model. The SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 days. Correlation analysis revealed that the C ₀ was significantly positively related with SOC content, soil total N (TN) and readily available K (AK) concentration. The labile soil carbon pool was significantly related to SOC and TN concentration, and significantly negatively correlated with soil bulk density. The intermediate carbon pool was positively associated with TN and AK. The stable carbon pool had negative correlations with SOC, TN and AK.

Snow damage on natural stands is an important problem concerning mountainous forest management. In the present research, the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees, stand and topography were studied in mountainous forests of northern Iran. A systematic sampling design was applied to the study area (140 ha), with 122 circular plots. The grid dimension was 100 m and each plot area was 1000 m². The four types of snow damage to trees include: crown damage (8.6%), stem breakage (5.4%), uprooting (3.2%), and bending (1.4%). The frequency of crown damage grew with an increase in the diameter at breast height (DBH), while the frequency of stem breakage, uprooting and bending decreased with an increase the DBH. The frequency of crown damage, stem breakage, and total damages was related to tree species (p < 0.01). Not all tree species were equally susceptible to snow damage. The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth. Young trees (DBH < 25 cm) were more susceptible to snow damage than other trees. Snow damage decreased by as the trees in the stand became more mixed in age. The susceptibility of trees to snow damage increased by height and slenderness coefficient. With adequate silvicultural operation, snow damage can be reduced to a minimum level in these natural forests.

Thinning of Korean pine (Pinus koraiensis Sieb. et Zucc.) is used to facilitate timber and cone production. The present study in Northeast China investigated the effects of thinning intensity on individual tree growth, temporal variation in cone yield, and seed quality in Korean pine plantation. In 2005, five thinning intensity levels (none, extreme, heavy, moderate and light) were set in 15 permanent plots in a 32-year-old Korean pine plantation at Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province. We recorded tree growth and seed cone production from 2013 to 2016, i.e., from 8 to 11 years after thinning. Except for height growth, thinning increased tree growth (diameter at breast height and crown size) and improved cone yield. The extreme thinning treatment (to 300 trees per hectare) resulted in the largest tree diameter, tree volume, crown size and 4-year cone production per tree. The highest cone yield per tree in the mast year (2014) was observed when stands were thinned to 500 trees per hectare (heavy thinning). Although the best cone and seed quality and the largest cone and seed mass per tree were recorded in the heavily thinned stand, no significant differences were found between heavy and moderate thinning stands (750 trees per hectare). At the stand level, the moderately thinned stand had the highest basal area, stock volume and seed cone production per stand. Our results suggest that thinning to 750 trees per hectare will improve timber and cone productivity in 40-year-old P. koraiensis stands.

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.

Intraspecific variability in morphological and ecophysiological leaf traits might be theorized to be present in declining populations, since they seem to be exposed to stress and plasticity could be advantageous. Here we focused on declining Persian oaks (Quercus brantii Lindl. var. persica (Jaub and Spach) Zohary) in the Zagros Mountains of western Iran, representing the most important tree species of this region. We selected trees with contrasting crown dieback, from healthy to severely defoliated, to investigate the relationships between canopy dieback and leaf morphology, water content and pigments. We also measured esterase and peroxidase, as enzymatic antioxidants and indicators of contrasting genotypes. Trees showing moderate to severe defoliation showed higher leaf mass area (LMA), reduced relative water content (RWC), and lower stomatal density (SD). Increasing LMA indicates a more sclerophyllic structure, according to drier conditions. We did not find significant differences in leaf pigments (chlorophyll a and b, and carotenoids) among crown dieback classes, suggesting that Persian oak trees are able to maintain accurate photochemical efficiency, while reduced RWC and SD suggest hydraulic limitations. Our results do not provide a consistent pattern as regards enzymatic antioxidant defense in Persian oak. Morphological leaf traits would be important drivers of future adaptive evolution in Persian oak, leading to smaller and thicker leaves, which have fitness benefits in dry environments. Nonetheless, drought responses may be critically affecting carbon uptake, as photosynthetic compounds are less effectively used in leaves with higher sclerophylly.

It is critical to understand how forests regenerate after the exclusion of human induced disturbances because the regenerating species drive the renewal of resources and ecosystems, which in turn support human beings locally and globally. This study of forest regeneration was conducted in the tropical coastal forest ecosystems of Tanzania at Uzigua Forest Reserve (24,730 ha) in the Pwani Region. We collected data from adult trees in 47 sampling plots (25 × 25 m) randomly established in closed forest sites (control) and in sites disturbed by farming and livestock grazing. Sapling and seedling data were collected and analyzed in 2 × 2 m nested subplots. Plots in the closed forest had higher mean basal area and volume for adult trees than those in sites disturbed by farming and livestock grazing. Plots in sites disturbed by farming had the highest Shannon–Wiener index for seedlings and saplings, followed by closed forest and livestock grazed sites. Closed plots and farmed plots had higher Simpson’s index for seedlings and saplings than in grazed sites. Plots in farmed and livestock-grazed sites had a higher Simpson index for adult trees than in closed sites. Equitability of seedlings and saplings was highest in closed forest sites, followed by farmed and livestock grazed sites. Plots disturbed by farming had higher equitability for adult trees than in livestock-grazed and closed sites. Moreover, plots disturbed by farming and grazing had a higher importance value index for seedlings than in closed sites. Plots in closed forests had higher sapling importance values than in farmed and grazed sites. Again, plots in closed forest had a higher importance value for adult trees than in farmed and grazed sites. The differences in tree species subcategories of regeneration across land-use indicates that farming and livestock grazing disturbances create heterogeneous microhabitats, which positively or negatively affects regeneration capacity of species after exclusion.

Climate change is predicted to alter global precipitation regimes. However, the response of soil carbon and nitrogen cycles and soil microorganisms to precipitation reduction is poorly understood but is dependent on ecosystem type. To evaluate the impacts of reduced precipitation on soil respiration, soil inorganic nitrogen (i.e., NH₄ ⁺–N and NO₃ ⁻–N), nitrogen mineralization, and soil microbial community composition, a precipitation manipulation experiment was initiated in a Mongolian pine plantation and a naturally restored grassland in semi-arid northeast China. Precipitation reduction led to decreases of soil respiration rates by 14 and 8% in 2014 and 2015 in the Mongolian pine plantation but no changes in the grassland. Soil inorganic nitrogen, ammonification and nitrification rate, and soil phospholipids fatty acids were not significantly changed by reduced precipitation but significantly differed between the two ecosystems and among growing seasons. Our results suggest that the impacts of precipitation reduction on soil respiration were different between the Mongolian pine plantation and the grassland, and that ecosystem type and growing season had more pronounced impacts on soil carbon and nitrogen cycles.

Plantation forests play a pivotal role in carbon sequestration in terrestrial ecosystems, but enhanced nitrogen (N) deposition in these forests may affect plantation productivity by altering soil N cycling. Hence, understanding how simulated N deposition affects the rate and direction of soil N transformation is critically important in predicting responses of plantation productivity in the context of N loading. This study reports the effects of N addition rate (0, 40, and 120 kg N ha⁻¹ a⁻¹) and form (NH₄Cl vs. NaNO₃) on net N mineralization and nitrification estimated by in situ soil core incubation and on-soil microbial biomass determined by the phospholipid fatty acid (PLFA) method in a subtropical pine plantation. N additions had no influences on net N mineralization throughout the year. Net nitrification rate was significantly reduced by additions of both NH₄Cl (71.5) and NaNO₃ (47.1%) during the active growing season, with the stronger inhibitory effect at high N rates. Soil pH was markedly decreased by 0.16 units by NH₄Cl additions. N inputs significantly decreased the ratio of fungal-to-bacterial PLFAs on average by 0.28 (49.1%) in November. Under NH₄Cl additions, nitrification was positively related with fungal biomass and soil pH. Under NaNO₃ additions, nitrification was positively related with all microbial groups except for bacterial biomass. We conclude that simulated N deposition inhibited net nitrification in the acidic soils of a subtropical plantation forest in China, primarily due to accelerated soil acidification and compositional shifts in microbial functional groups. These findings may facilitate a better mechanistic understanding of soil N cycling in the context of N loading.

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.

Santalum album L. is a commercially important tree that yields essential oil of high medicinal value. Regeneration research through organogenesis and embryogenesis has been documented but no report depicts comparative ontogeny of directly differentiating shoot buds (SB) and somatic embryos (SE). In the present study aseptic seedling derived hypocotyl segments (HC) and hypocotyl + root junction (HC + R) were used to induce SBs and SEs, respectively. Ontogenic differences between the structures were confirmed using scanning electron microscopy and histological analysis. MS medium containing 6-benzyladenine or BA (2.5 µM) produced highest number of direct SB, while MS + BA (7.5 µM) proved suitable for higher frequency of SE differentiation. The differentiating structures attained growth when transferred to MS medium containing a combination of BA and α-naphthalene acetic acid or silver nitrate (AgNO₃). A combination of indole-3-butyric acid and silver nitrate (AgNO₃) in half-strength woody plant medium and lesser osmotic concentration (2% sucrose), induced rhizogenesis.

Root/shoot (R/S) ratio is an important index for assessing plant health, and has received increased attention in the last decades as a sensitive indicator of plant stress induced by chemical or physical agents. The R/S ratio has been discussed in the context of ecological theory and its potential importance in ecological succession, where species follow different strategies for above-ground growth for light or below-ground competition for water and nutrients. We present evidence showing the R/S ratio follows a biphasic dose–response relationship under stress, typical of hormesis. The R/S ratio in response to stress has been widely compared among species and ecological succession classes. It is constrained by a variety of factors such as ontogeny. Furthermore, the current literature lacks dose–response studies incorporating the full dose–response continuum, hence limiting scientific understanding and possible valuable application. The data presented provide an important perspective for new-generation studies that can advance current ecological understanding and improve carbon storage estimates by R/S ratio considerations. Hormetic response of the R/S ratio can have an important role in forestry for producing seedlings with desired characteristics to achieve maximum health/productivity and resilience under plantation conditions.

Understanding physiological responses and drought adaptation strategies of woody plant leaf traits in sub-humid to semi-arid regions is of vital importance to understand the interplay between ecological processes and plant resource-allocation strategies of different tree species. Seasonal variations of leaf morphological traits, stoichiometric traits and their relationships of two drought tolerant woody species, live oak (Quercus virginiana) and honey mesquite (Prosopis glandulosa) and two less drought tolerant species, sugarberry (Celtis laevigata) and white ash (Fraxinus americana) were analyzed in a sub-humid to semi-arid area of south Texas, USA. Our findings demonstrate that for the two drought tolerant species, the leguminous P. glandulosa had the highest specific leaf area, leaf N, P, and lowest leaf area and dry mass, indicating that P. glandulosa adapts to an arid habitat by decreasing leaf area, thus reducing water loss, reflecting a resource acquisition strategy. While the evergreen species Q. virginiana exhibited higher leaf dry mass, leaf dry matter content, C content, C:N, C:P and N:P ratios, adapts to an arid habitat through increased leaf thickness and thus reduced water loss, reflecting a resource conservation strategy in south Texas. For the two less drought tolerant deciduous species, the variations of leaf traits in C. laevigata and F. americana varied between Q. virginiana and P. glandulosa, reflecting a trade-off between rapid plant growth and nutrient maintenance in a semi-arid environment.

Two threatened dipterocarp species, Dipterocarpus costatus and Dipterocarpus alatus are well-known endangered species in lowland forests of southeastern Vietnam, primarily from habitat loss and over-exploitation of their wood. To develop conservation strategies for these species, we analyzed 242 samples using nine microsatellite markers to determine the genetic variability within and among five populations of D. alatus and three of D. costatus, representing the natural range of dipterocarps in Southeast Vietnam. Results indicated low levels of genetic variability within populations with an average gene diversity of 0.223 for D. alatus and 0.152 for D. costatus. Results of bottleneck tests indicated a reduction in population size of both species (P > 0.05). Genetic differentiation among populations was high (F _ST = 0.347 for D. costatus and 0.274 for D. alatus), indicating limited gene flow (N _m = 0.662 for D. costatus and 0.47 for D. alatus) and isolated populations related to geographical distances. Analysis of molecular variance showed high genetic variation within populations (72.92% for D. alatus and 60.81% for D. costatus) compared to among populations. Bayesian analysis and UPGMA tree also indicated the two optimal genetic clusters related to geographical distances. These results will provide a platform for the conservation, management and restoration of these species.

CBF/DREB proteins play a critical role in abiotic stress-mediated gene expression and represent attractive regulons for plant breeding programs. However, no study has been conducted for CBF/DREB protein-related genes in jujube (Ziziphus jujuba Mill.). In this study, twenty-five ZjDREB genes were identified and annotated from the jujube (Z. jujuba ‘Dongzao’) genome. Detailed analysis, including gene classification, annotation, phylogenetic evaluation, conserved motif determination and expression profiling were performed on all genes. Phylogenetic analysis showed that ZjDREB proteins were divided into five subgroups (A1–A5), but lacking a subgroup A6 corresponding to AtDREBs. The ZjDREB genes were distributed in nine of twelve chromosomes in the genome. Additionally, the expression patterns of the DREB genes under different abiotic stresses were investigated using qRT-PCR. Nineteen ZjDREB genes were down-regulated under low temperature, in contrast six ZjDREB genes (01, 03, 05, 11, 23 and 24) were up-regulated. Under drought, salinity and high temperature conditions, expression of ZjDREB03, 09, 10, 14, 15, 17 and 20 genes were induced and showed similar expression patterns, suggesting that various stress conditions share common elements in the signaling pathway. The results suggest that the family of DREB genes play an important role in abiotic stresses in jujube, and provide a foundation for further functional studies of this important class of transcriptional regulators.

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.

RNA-seq and single-cell genomic research emerge as an important research area in the recent years due to its ability to examine genetic information of any number of single cells in all living organisms. The knowledge gained from RNA-seq and single-cell genomic research will have a great impact in many aspects of plant biology. In this review, we summary and discuss the biological significance of RNA-seq and single-cell genomic research in plants including the single-cell DNA-sequencing, RNA-seq and single-cell RNA sequencing in woody plants, methods of RNA-seq and single-cell RNA-sequencing, single-cell RNA-sequencing for studying plant development, and single-cell RNA-sequencing for elucidating cell type composition. We will focus on RNA-seq and single-cell RNA sequencing in woody plants, understanding of plant development through single-cell RNA-sequencing, and elucidation of cell type composition via single-cell RNA-sequencing. Information presented in this review will be helpful to increase our understanding of plant genomic research in a way with the power of plant single-cell RNA-sequencing analysis.

Variations in the phenotypic characteristics of conifer needles is a consequence of genetic evolution that has been widely used in geographic variation and ecological studies. Although many studies are based on an in situ sampling strategy and generally realize the contribution of environmental effects to variation in needle traits, it is still uncertain which needle traits are most influenced by genetic effects and which are most influenced by the environment. Using both a common garden experiment to eliminate environmental heterogeneity and an in situ sampling strategy, we compared 18 Pinus tabuliformis needle traits among 10 geographical populations. Using both sampling strategies, we found significant differences in needle traits among populations and among individuals within populations. Differences in the “among-population” variance component between the two sampling strategies revealed the environmental contribution among natural populations for each trait. The among-population variance in the following traits exceeded 8%: needle length, number of stomata within 2 mm (NS2), number of stomatal lines on the planar side, number of resin canals (RCN) and the resin canal area (RCA). For the stability of needle traits, NS2, RCN, RCA, ratio of the vascular bundle area to the RCA (VBA/RCA), and MA/RCA differed significantly in more than five provenance changes between the common garden populations and natural populations, which may be susceptible to environmental effects. Conversely, the cross-sectional area, mesophyll area (MA), MA/(VBA + RCA), and MA/VBA were phenotypically stable. Geographic variation patterns and systematic relation of needle traits differed between the two sampling strategies, suggesting that in situ sampling results may reflect environmental effects and deviate statistical parameters for genetic study. Future studies of genetic evolution in the context of geographic variation should be based on appropriate sampling strategies and stable phenotypic traits.

Microbial indices and their spatial patterns are strongly affected by environmental factors. Spatial variability of soil properties is one of the most important causes of variability in soil microbial indices. This research was conducted in the Caspian forest to assess spatial variabilities and frequency distributions of microbial properties. Ninety soil samples were taken using a grid sampling design 40 × 40 m. Microbial indices, organic carbon, nitrogen and pH were determined. Soil variable distributions showed that microbial indices had abnormal distributions. Logarithmic transformation produced normal distribution. Spatial continuity using geostatistical (variogram) was studied and maps obtained by point kriging. The variograms revealed the presence of spatial autocorrelation. The results indicate that spatial dependence of soil microbial indices was affected by non-intrinsic factors and forest management procedures. The maps show that soil microbial indices and soil properties have spatial variability. The spatial pattern of microbial indices was correlated to organic carbon and nitrogen.

To understand the decomposition characteristics of Pinus massoniana foliar litter and the degradation of its refractory compounds in plantations under five canopy densities, a litter bag experiment over a decomposition time of 392 days was carried out. The results show that canopy density significantly affected decomposition rates of litter and degradation rate of lignin and cellulose. Litter decomposition rates decreased significantly with decreasing canopy density. Both lignin and cellulose degradation rates were lower with canopy densities of 0.62 and 0.74 as compared with the three other densities. Lignin and cellulose losses were more rapid in the first 118 days. Soil fauna had significant impacts on litter decomposition and the degradation of refractory compounds. Canopy density had significant effects on factors such as soil properties and soil fauna community structure, which could be conducive to the decomposition of litter and the degradation of litter recalcitrant components. Canopy density between 0.6 and 0.7 might be a favorable management practice promoting litter decomposition and beneficial for the sustainable development of P. massoniana plantations.