Natural resource statistics are often unavailable for small ecological or economic regions and policymakers have to rely on state-level datasets to evaluate the status of their resources (i.e., forests, rangelands, grasslands, agriculture, etc.) at the regional or local level. These resources can be evaluated using small-area estimation techniques. However, it is unknown which small area technique produces the most valid and precise results. The reliability and accuracy of two methods, synthetic and regression estimators, used in small-area analyses, were examined in this study. The two small-area analysis methods were applied to data from Jalisco’s state-wide natural resource inventory to examine how well each technique predicted selected characteristics of forest stand structure. The regression method produced the most valid and precise estimates of forest stand characteristics at multiple geographical scales. Therefore, state and local resource managers should utilize the regression method unless appropriate auxiliary information is not available.

The taper functions of Kozak (1988), Bi (2000) and Fang et al. (2000) were comparatively analyzed in the present paper to develop a system for calculating the merchantable volume of oaks in the northwestern region of the state of Chihuahua (Mexico). Taper data corresponding to 298 trees were collected in mixed and uneven-aged pine-oak stands located throughout the study area, and covering the existing range of ages, stand densities and sites. Results show that the compatible segmented model developed by Fang et al. (2000) best described the experimental data and is therefore recommended for estimating tree diameter at a specific height, height to a specific diameter, merchantable volume, and total volume for oaks. The equation developed in this study is a fundamental tool for use in forest surveys in the study region and is simple enough to ensure its operational implementation. The results of the statistical analysis show that the equation can be recommended for other regions, although some local adaptations may be needed.

The soil respiration rates (R _h) in 6-year-old (young), 17-year-old (middle-age), 31-year-old (mature) Casuarina equisetifolia coastal plantations were measured using an LICOR-8100 automated soil CO₂ flux system from May 2006 to April 2007. Results show that R _h displayed an obvious seasonal pattern across the observed years. The maximum values of R _h occurred at June and July and the minimum at December and January. Soil temperature and soil moisture as well as their interaction had significant effects on the monthly dynamics of R _h. The analysis by one-way ANOVA showed that R _h had a significantly exponential relation (p<0.05) to soil temperature at soil depth of 5 cm, and had a linear relation (p<0.05) to soil water content of the upper 20 cm. The result estimated by the two-factor model shows that soil temperature at soil depth of 5 cm and soil moisture at soil depth of 20 cm could explain 68.9%–91.9% of seasonal variations in R _h. The order of R _h rates between different stand ages was middle-age plantation>mature plantation>young-age plantation. With the increase of growth age of plantation, the Q ₁₀ of R _h increased. The contribution of R _h to total soil surface CO₂ flux was 71.89%, 71.02% and 73.53% for the young, middle-age and mature plantation, respectively. It was estimated that the annual CO₂ fluxes from R _h were 29.07, 38.964 and 30.530 t·ha⁻¹·a⁻¹ for the young, middle-age and mature plantation, respectively.

One-year-old seedlings of Dalbergia sissoo from a single provenance were planted in non-weighing lysimeter tanks in July 1998 with a view to provide optimize irrigation parameters in desert areas. Varying water regimes were maintained by re-irrigating the seedlings at 36.2 mm (W₁), 26.5 mm (W₂), 20.2 mm (W₃) and 18.1 mm (W₄) treatments when the soil water content decreased to 7.56%, 5.79%, 4.44%, 3.23% in the respective treatments. Height, collar diameter, number of leaves and leaf area were highest (p < 0.01) for the seedlings irrigated at W₁ level. Above-mentioned growth parameters did not differ between W₁ and W₂ treatments but the seedlings in W₂ level had highest biomass per liter of water use (i.e., water use efficiency, WUE). Irrigation levels of W₃ to W₅ negatively affected seedling growth, biomass production and nutrient accumulation. Soil water availability below W2 level (i.e., 5.79%) caused an increase in percentage of root biomass to the total biomass of the seedling. However, there was a decrease in percentage of leaf dry biomass in W₃ and W₄ treatments and in percentage of stem dry biomass in the seedlings of W₅ treatment. Seedlings in W₅ treatment survived till at soil water potential of −1.96 MPa. Limitation of soil water availability in W₃ and W₄ treatments affected growth and biomass production of D. sissoo seedlings. W₂ level was best for growth and biomass production in which water use efficiency was highest. Therefore, better growth and biomass production of D. sissoo seedlings could be obtained by irrigating the seedlings at soil water content of ≥5.79% in the loamy sand soil.

The partitioning of nitrogen deposition among forest soil (including forest floor), leachate and above- and belowground biomass of pot cultured beech seedlings in comparison to non-cultured treatments were investigated by adding 1.92 g·m^{−2 15}N tracer in throughfall for two successive growing seasons at a greenhouse experiment. Ammonium and nitrate depositions were simulated on four treatments (cultured and non-cultured) and each treatment was labeled with either ¹⁵N-NH₄ ⁺ or ¹⁵N-NO₃ ⁻. Total recovery rates of the applied ¹⁵N in the whole system accounted for 74.9% to 67.3% after ¹⁵N-NH₄ ⁺ and 85.3% to 88.1% after ¹⁵N-NO₃ ⁻ in cultured and non-cultured treatments, respectively. The main sink for both ¹⁵N tracers was the forest soil (including forest floor), where 34.6% to 33.7% of ¹⁵N-NH₄ ⁺ and 13.1% to 9.0% of ¹⁵N-NO₃ ⁻ were found in cultured and non-cultured treatments, respectively, suggesting strong immobilization of both N forms by heterotrophic microorganisms. Nitrogen immobilization by microorganisms in the forest soil (including forest floor) was three times higher when ¹⁵N-NH₄ ⁺ was applied compared to ₁₅N-NO₃ ⁻. The preferential heterotrophic use of ammonium resulted in a two times higher retention of deposited ¹⁵N-NH₄ ⁺ in the forest soil as compared to plants. In contrast, nitrate immobilization in the forest soil was lower compared to plants, although statistically it was not significantly different. In total the immobilization of ammonium in the plant-soil system was about 60% higher than nitrate, indicating the importance of the N-forms deposition for retention in forest ecosystems.

After subjecting the seeds to GA₃, and H₂O₂ treatments for 24 h and chilling at 2–3°C for a period of 15 days, we conducted the seed germination tests for 21 different seed sources of Pinus roxburghii from western-central Himalaya under laboratory conditions at various temperatures viz., 20°C, 25°C and 30°C inside a seed germinator. The results reveal that the soaking of seeds in H₂O₂ (1% v/v) and GA₃ (10 mg·L⁻¹) solutions manifested 82.39% and 78.19% germination, respectively whereas untreated seeds exhibited 70.79% average germination. Both GA₃ and H₂O₂ treatments caused an appreciable shortening of the germination period by 8 days and 10 days, respectively. Moist-chilling did improve the rate and percentage of germination when germinated at 20°C over 21 days; however total germination was not affected at temperatures 25°C and 30°C. Although the seeds of P. roxburghii germinate well due to lack of dormancy, the increasing demand for large quantities of seeds of P. roxburghii for reforestation programmes make pre-sowing treatments useful in improving the rate and percentage of germination.

A study was conducted to evaluate the effects of sludge (industrial and residential) on seed germination and growth performance of Acacia auriculiformis seedlings at the nursery of Institute of Forestry and Environmental Sciences, Chittagong University (IFESCU), Bangladesh. Before sowing of the seeds, different combinations of sludge were incorporated with the nutrient-deficient natural forest soils. Seed germination and growth parameters of the seedlings (shoot and root length, collar diameter, fresh and dry weight of shoot, and root and total dry biomass) were recorded after one, two and three months of seed sowing. Physio-chemical parameters (pH, organic carbon, nitrogen, phosphorus, and potassium) and heavy metals (chromium, nickel, manganese, cadmium and zinc) of each treatment were also analyzed before sowing of seeds and after harvesting of seedlings. Results show that the seed germination percentage and the seedling growth parameters varied significantly in the soil added with sludge in comparison to control. The highest germination percentage (90%) was observed in the treatment of soil with residential sludge of 2:1 compared to control. The highest growth and biomass of the seedlings as well as the maximum percentage of organic carbon and nutrients (N, P and K) were also recorded in the same combination. Soil added with industrial sludge had a higher concentration of heavy metal than that of residential sludge. The highest concentrations of heavy metals were found in soil added with industrial sludge of 1:1. It is recommended that soil added with residential sludge of 2:1 provide good condition for better seed germination and growth of A. auriculiformis seedlings in degraded forest soil.

The response of Kousa dogwood (Cornus kousa Buerg.) to extreme stresses was investigated by RGB image analysis in the hot, dry and windy summer in 2007 in Yamaguch, Japan. Results show that tip and margin leaf scorch was observed on many Kousa dogwood trees and clearly dark brown defense barrier appeared on scorched leaves. The defense barrier withdrew back from distal to proximal gradually until successful control of scorching, and left a series of unsuccessful defense traces. By responsive analysis of leaf color homogeneity with RGB image analysis method, a sharp logistic equation was obtained for the relative green/luminance (RGL) value of scorched leaves. By the meteorological analysis, the occurrence of dogwood leaf scorch-back was almost synchronous with the aridity peak period. It suggested that during the sudden aridity increment the extreme water stresses induce the defense response of Kousa dogwood tree to shear the excessive transpiration leaf area, and prevent the rest of the trees from further water loss. Image pixel analysis showed that 40.2% leaf area of sampled dogwood trees was reduced through the partial leaf scorch-back by the end of August in 2007. In contrast, only 13.2% leaf area was reduced from the same trees in 2008, for the reason of sufficient precipitation during first half year. In any case, the Kousa dogwood trees indeed reduced their transpiration surface area and appeared a surface reduction pattern differing from those shedding leaves or withering all the aboveground. Based on desiccation process analysis, it is considered that the interaction of the leaf dried back and the self-defense response was the key of the transpiration surface reduction (TSR) of Kousa dogwood during sudden hot and droughty stresses.

The ultrastructural distribution and active location of ATPase and the ultrastructural variations were investigated in mesophyll cells of Cyclocarya paliurus seedlings after iso-osmotic salt/water treatments in combination with calcium regulation. C. paliurus seedlings were treated with five groups (control, 85 mM NaCl, 85 mM NaCl + 12 mM Ca(NO₃)₂, PEG iso-osmotic to 85 mM NaCl and PEG iso-osmotic to 85 mM NaCl +12 mM Ca(NO₃)₂) in a hydroponic system in a phytotron. Results show that under normal growth conditions, the ATPase activity was low and the enzyme was primarily located on the nucleus. After 12 days of iso-osmotic salt/water treatments, ATPase activity on the tonoplast increased. Osmiophilic globules for iso-osmotic water treatment were greater than that for iso-osmotic salt treatments. The ATPase activity increased and was mostly transferred onto the nucleus for calcium regulation treatment under iso-osmotic salt/water stresses, and the osmiophilic globules significantly decreased under iso-osmotic water stress with calcium regulation. The ATPase located on the nucleus indicated that the degree of salt/drought damage that seedlings suffered was slighter, while the amount of the enzyme located on the tonoplast showed that the degree of salt/drought damage there was more serious. After 4 and 20 days of isoosmotic treatments, the injury suffered by the leaf ultrastructures of C. paliurus seedlings for iso-osmotic treatment with calcium regulation was lower than those without calcium regulation, especially for the iso-osmotic water treatments. Preliminary analysis suggests that the injury suffered by C. paliurus seedlings was lower for iso-osmotic salt treatments than for iso-osmotic water treatments, while the effect of calcium regulation under iso-osmotic water stress was greater than that of the iso-osmotic salt stress.

The composition and density of seeds in soils of secondary forests derived on abandoned fields after 4, 9 and 14 years of abandonment were quantified to examine whether the soil seed bank assembles during secondary succession as the plant communities assemble. A total of 18, 37 and 48 soil samples from 4-, 9- and 14-year old sites, respectively were collected in 15 cm × 15 cm plots up to 9 cm depth. A total of 3, 5 and 9 species were found on sites abandoned 4, 9 and 14 years ago, respectively. Among different life forms, trees were highly represented in the soil seed bank of 9-year (60%) and 14-year (33%) old sites compared to 4-year old site entirely dominated by nonwoody flora. The total number of seeds ranged from 327 in the 4-year old site to 146 in the 14-year old site, and the corresponding density of viable seeds ranged from 141 seeds ·m⁻² in the 4-year old site to 26 seeds m⁻² in the 14-year old site with a consistent decreasing pattern in the chronosequence. The similarity between the soil seed flora and the standing woody vegetation was low for both 9- and 14-year old sites while complete dissimilarity was found for 4-year old site. We concluded that the species composition of soil seed banks assemble gradually during secondary succession, but the overall seed density is still low for natural regeneration of trees to rely on. To expedite the recovery of secondary forests on such abandoned fields, the seed bank needs to be supplemented by direct seeding, enrichment planting of desired species and installing artificial perches for facilitating seed dispersal.

The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments (graded, adjacent, intermediate and ungraded areas) along paved and unpaved roads in West Africa. A total of 203 quadrats of 2 m × 5 m in size were surveyed and placed along transects parallel to the roads. Within each quadrat, the total number of seedlings and the number of living shoots per seedling base were recorded. Regeneration mechanisms were determined by assessing basal and aerial sprouts and excavating the root systems below ground level. The results show that the total seedling density and the densities of single- and multi-stemmed individuals varied significantly (p < 0.05) among the four roadside environments. However, all seedlings were produced asexually; root suckers were predominant (98%) compared to water sprout (1%) and coppices (less than 1%). This study demonstrates that an intermediate level of soil disturbance from grading along paved and unpaved roads may stimulate P. suberosa regeneration by root suckering. Road type (paved and unpaved) did not affect seedling density, but was a highly significant variable in relation to the coppicing ability of P. suberosa populations in roadside sites. In conclusion, P. suberosa is a disturbance-tolerant species which can proliferate mainly by root suckering after roadwork disturbance.

The greenness (SPAD) of uneven-aged leaves of dominant species in the Castanopsis carlessi forest at different altitude gradients in Lingshishan National Forest Park, Fujian Province, China were measured by using portable chlorophyll meter SPAD-502. In addition, the correlation between SPAD value and the concentration of chlorophyll and foliar nitrogen was also investigated. Significant variations in SPAD values were found between the uneven-aged leaves of different dominant species and different altitude gradients. Regression analysis showed that SPAD value was significantly correlated with the concentration of chlorophyll and the content of foliar nitrogen, indicating that SPAD value could be indicators for foliar chlorophyll and nitrogen. It is suggested that SPAD meter is a useful tool for forest assessments in decision-making and operational nutrient management programs.

A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula platyphylla forest in Changbai Mountain from May to September in 2004. Results indicated that the total soil respiration, root-severed soil respiration and the root respiration followed a similar seasonal trend, with a high rate in summer due to wet and high temperature and a low rate in spring and autumn due to lower temperature. The mean rates of total soil respiration, root-severed soil respiration and root respiration were 4.44, 2.30 and 2.14 µmol·m⁻²·s⁻¹, respectively during the growing season, and they were all exponentially correlated with temperature. Soil respiration rate had a linear correlation with soil volumetric moisture. The Q₁₀ values for total soil respiration, root-severed soil respiration and root respiration were 2.82, 2.59 and 3.16, respectively. The contribution rate of root respiration to the total soil respiration was between 29.3% and 58.7% during the growing season, indicating that root is a major component of soil respiration. The annual mean rates of total soil respiration, root-severed soil respiration and root respiration were 1.96, 1.08, and 0.87 µmol·m⁻²·s⁻¹, or 741.73, 408.71, and 329.24 g·m⁻²·a⁻¹, respectively. Root respiration contributed 44.4% to the annual total soil respiration. The relationship proposed for soil respiration with soil temperature was useful for understanding and predicting potential changes in Changbai Mountain B. platyphylla forest ecosystem in response to forest management and climate change.

A study was conducted to explore the defense response in woody plants after insect herbivory. The activities of two enzymes, lipoxygenase (LOX), a key enzyme of jasmonate (JA) pathway, and phenylalanine ammonia lyase (PAL), a rate-limiting enzyme of phenylpropanoid pathway, were measured in the leaves of one-year-old poplar (Populus simonii × P. pyramidalis ‘Opera 8277’) cuttings after Clostera anachoreta larvae attack. The results show that the increased activities of LOX and PAL were found not only in the leaves wounded by C. anachoreta larvae but also in their upper systemic leaves, indicating that JA and phenylpropanoid pathways were activated, and the defense response was stimulated systemically. The increase in LOX and PAL activities in neighboring intact poplar cuttings suggested that there exists the interplant communication between poplar plants mediated by the herbivore-induced volatiles. Methyl jasmonate (MeJA) was also proved to be an airborne signal to induce defense response in P. simonii × P. pyramidalis ‘Opera 8277’ cuttings.

The heartwood of teak in certain areas of Java Island displays irregular black streaks along the annual rings. We investigated the color and chemical characteristics in a radial direction of partially black-streaked heartwood samples. Color properties (pH value, inorganic element, extractive content and extractive characterization) were measured in the color co-ordinates CIELAB system. The results show that the black streak part was 12–15 brightness (L*) value units less than the normal heartwood. Furthermore, the black streak part had more red (a*) but less yellow (b*), hue (h) and chroma (C*) than the normal wood. The pH value, ash content and calcium contents of the black streak part were slightly higher than those obtained for the normal wood. The content of the low-polar extractive (n-hexane and ethyl acetate) of the black streak part was considerably higher than that for the normal wood. The blackening process was speculated to be a kind of defense mechanism indicated by remarkable amount of bioactive compound called tectoquinone.

A new breeding population of Mandarin Duck (Aix galericulata, Linnaeus) was first recorded in 2003 in Jiaotanzhuang-Hehekou region of Pingshan county, Hebei Province, China. Recently, the gradually increasing population indicates that there are suitable breeding habitats (such as foraging habitats and nesting sites) for Mandarin Duck. However, these habitats are always close to human disturbances, which are the potential risk for their population. Therefore, it is urgent to put forward an applicable protection strategy, in order to strengthen the public awareness for this unprotected population.

This review describes the effects of ultraviolet-B (UV-B) radiation on plant growth and development, photosynthesis and photosynthetic pigments and UV-B absorbing compounds. Moreover, plant ecosystem level responses to elevated UV-B radiation and interactions of UV-B radiation with abiotic and biotic factors were also involved. Results collected in this review suggest that approximately two-thirds terrestrial plant species are significantly affected by increase in UV-B radiation. The majority of evidences indicate that elevated UV-B radiation is usually detrimental but there exists tremendous variability in the sensitivity of species to UV-B radiation, and sensitivity also differs among cultivars of the same species.