不同密度山地速生工业原料林生物量的研究

通过对4年生马褂木、邓恩桉、杜英3个树种不同密度条件下山地林分生物量的调查分析,结果表明:①4年生林分平均胸径5.08 cm,树高4.96 m,蓄积25.52 m3/hm2;平均单株生物量4.18 kg,其中树干2.95 kg,树皮0.36 kg,树枝0.73 kg,树叶0.20 kg;林分平均总生物量达到16.98 t/hm2,其中树干10.43 t/hm2,树皮1.29 t/hm2,树枝2.25 t/hm2,树叶0.71 t/hm2,凋落物2.53 t/hm2;②不同密度不同树种的林分生物量存在极显著差异,1.0 m×1.8 m密度极显著大于其它密度,马褂木极显著大于其它树种.1.0 m × 1.8 m密度的马褂木林分生物量达到41.71t/hm2;极显著大于其它林分,可以作为山地短轮伐期工业原料林的主要经营模式;③在空间分布上,山地工业原料林单株生物量由基部向上逐渐减少,呈塔形分布,树干和树皮生物量主要集中在树体的1/2树高以下,枝叶主要集中在中间区段,马褂木在3～6 m树高处,邓恩桉在3～5 m树高处,杜英在1～4 m树高处,是整个林分光合作用的主要层面.     

Changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the Black Rock Forest, Hudson Highlands, southeastern New York State

We sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (AGB) over 76 years (1930-2006) in the deciduous Black Rock Forest in southeastern New York, USA. We used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate AGB and carbon content. Between the early 1930s and 2000, three species were extirpated from the forest (American elm (Ulmus americana L.), paper birch (Betula papyrifera Marsh.) and black spruce (Picea mariana (nigra) (Mill.) BSP)) and seven species invaded the forest (non-natives tree-of-heaven (Ailanthus altissima (Mill.) Swingle) and white poplar (Populus alba L.) and native, generally southerly distributed, southern catalpa (Catalpa bignonioides Walt.), cockspur hawthorn (Crataegus crus-galli L.), red mulberry (Morus rubra L.), eastern cottonwood (Populus deltoides Bartr.) and slippery elm (Ulmus rubra Muhl.)). Forest canopy was dominated by red oak and chestnut oak, but the understory tree community changed substantially from mixed oak-maple to red maple-black birch. Density decreased from an average of 1500 to 735 trees ha(-1), whereas basal area doubled from less than 15 m(2) ha(-1) to almost 30 m(2) ha(-1) by 2000. Forest-wide mean AGB from inventory data increased from about 71 Mg ha(-1) in 1930 to about 145 Mg ha(-1) in 1985, and mean AGB on the long-term plots increased from 75 Mg ha(-1) in 1936 to 218 Mg ha(-1) in 1998. Over 76 years, red oak (Quercus rubra L.) canopy trees stored carbon at about twice the rate of similar-sized canopy trees of other species. However, there has been a significant loss of live tree biomass as a result of canopy tree mortality since 1999. Important constraints on long-term biomass increment have included insect outbreaks and droughts.     

Above- and belowground biomass and primary productivity of a Larix gmelinii stand near Tura, central Siberia

We assessed above- and belowground biomass and net primary production (NPP) of a mature Larix gmelinii (Rupr.) Rupr. forest (240-280 years old) established on permafrost soils in central Siberia. Specifically, we investigated annual carbon budgets in roots in relation to root system development and availability of soil resources. Total stand biomass estimated by allometry was about 39 Mg per ha. Root biomass (17 Mg per ha) comprised about 43% of total biomass. Coarse root (>/= 5 mm in diameter) biomass was about twice that of fine roots (< 5 mm). The aboveground biomass/root biomass ratio (T/R) of the larch stand was about unity, which is much less than that of other boreal and subalpine conifer forests. The proportion of fine roots in total root biomass (35%) was relatively high compared with other cold-climate evergreen conifer forests. Total NPP, defined as the sum of annual biomass increment of woody parts and needle biomass, was estimated to be 1.8 Mg per ha per year. Allocation of total NPP to needle production was 56%. The proportion of total NPP in belowground production (27%) was less than for evergreen taiga forests. However, belowground NPP was probably under-estimated because root mortality was excluded. We conclude that L. gmelinii trees invested annual carbon gains largely into needle production or roots, or both, at the expense of growth of aboveground woody parts. This carbon allocation pattern, which resulted in the construction of exploitative root networks, appeared to be a positive growth response to the nutrient-poor permafrost soil of central Siberia.     

Effect of pollarding frequency on biomass of Erythrina poeppigiana as a coffee shade tree

The use of pollarded Erythrina poeppigiana as shade tree in coffee plantations is apparently an old practice in Costa Rica. The tree is not native to this country but was introduced between late 19th and 20th century and was rapidly dispersed in the coffee and cacao areas. Currently, the Erythrina tree is widespread in the Turrialba Valley (elevation 600—1300m) and in the Central Valley (elevation 1200m) where the species is always associated with present or past coffee crops. Pollarding carried out by Costa Rican farmers constitutes a long dated and functional practice, hence the objective of this study was to evaluate the amount of biomass produced by pollarding of Erythrina poeppigiana used as shade in coffee crop planted at a density of 280 trees/hectare under different pollarding frequencies. Results showed that by pollarding once a year, 18,470 kg of dry matter per hectare are produced; with two pollardings per year 11,800 kg/ha are produced and with three pollarding per year 7,850 kg/ha are produced. The total amount of nitrogen removed is very similar for pollarding once and twice a year, but is lower for three times a year. The amount of nitrogen removed was approximately 230 kg/ha/year in the first two cases and 170 kg/ha/year in the last one.The above observations suggest that a considerable supply of nutrients exist in the systems with shade trees, when they are periodically pollarded.Finally some conclusions and follow up activities related to research on the species are suggested, such as higher biomass production techniques, appropriate planting practices, selection of genetic material, nutrient depletion when biomass is harvested, conversion of leaves to marketable feed sources (flour, pellets), alley cropping and green manure production and restoration of degraded areas and improductive savannas by planting large cuttings that would improve the soil by adding biomass and shade out undesirable grasses.This work is part of a Ph.D. Dissertation submitted to the Southeastern University, New Orleans, Lousiana by R.O. Russo.     

Impacts of fructification on biomass production and correlated genetic effects in Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.)

For the period 2003–2006, fructification of Norway spruce (Picea abies [L.] Karst.) was recorded at the Kranzberg forest site in Southern Germany by employing a crane with access to the canopy of more than 266 trees. For each tree, stem diameter and growth parameters were assessed annually as well as biomass of cones and seeds, number of seeds per cone, and proportions of empty seeds for a total of 371 trees with cone crop. Genotypes at 19 enzyme coding gene loci of 110 trees were included in the study of correlations between morphological and genetic traits. Re-scaling the observed values for a virtual pure Norway spruce stand of 1 ha, cone biomass including winged seeds (oven-dried at 38°C) varied between 706.8 kg/ha in 2006 (average value per tree was 3.6 kg) and values close to zero in 2005. Corresponding values for vegetative biomass increment of the coning trees in 2006 were 9,273.0 kg/ha and 10.8 kg/tree. A significant higher biomass investment was determined for dominant trees in terms of absolute cone mass as well as in terms of cone mass relative to vegetative biomass and fructification frequency. No trade-off effects in decreased vegetative biomass growth were found in the fructification year, compared to trees that did not grow cones. Although the dominant trees invested proportionally considerable biomass in cones, they showed no significant reduction in vegetative biomass growth. In the following year no decrease in vegetative growth was detected. Based on logistic regressions and homogeneity tests, respectively, significant genetic effect became evident with respect to the gene loci AAP-B and AAT-C concerning fructification probability in the year with maximum generative biomass investment. These and closely related loci also have been found to be indicative for growth and viability, respectively, in other species.     

Carbon storage in biomass,litter, and soil of different plantations in a semiarid temperate region of northwest China

? Context

A large area of abandoned land in the semiarid temperate region of China has been converted into plantations over the past decades. However, little information is available about the ecosystem C storage in different plantations.

? Aim and methods

Our objective was to estimate the C storage in biomass, litter, and soil of four different plantations (monospecific stands of Larix gmelinii, Pinus tabuliformis, Picea crassifolia, and Populus simonii). Tree component biomass was estimated using allometric equations. The biomasses of understory vegetation and litter were determined by harvesting all the components. C fractions of plant, litter, and soil were measured.

? Results

The ecosystem C storage were as follows: Picea crassifolia (469 t C/ha)?>?Larix gmelinii (375 t C/ha), Populus simonii (330 t C/ha)?>?Pinus tabuliformis (281 t C/ha) (P?<?0.05), 59.5–91.1 % of which was in the soil. The highest tree and understory C storage were found in the plantation of Pinus tabuliformis (247 t/ha) and Larix gmelinii (1.2 t/ha) respectively. The difference in tree C fraction was significant among tree components (P?<?0.05), following the order: leaf?>?branch?>?trunk?>?root. The highest soil C (SC) was stored in Picea crassifolia plantation (411 t C/ha), while Populus simonii plantation had a higher SC sequestration rate than others.

? Conclusion

C storage and distribution varied among different plantation ecosystems. Coniferous forests had a higher live biomass and litter C storage. Broadleaf forests had considerable SC sequestration potential after 40 years establishment.     

The inventory of the carbon stocks in sub tropical forests of Pakistan for reporting under Kyoto Protocol

The United Nations Framework Convention on Climate Change (UNFCCC) requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broad leaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine (Pinus roxburghii) forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory carried out from 2005 to 2010. In total 261 plots (each of 1ha.) were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above-and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature (~100 years old) pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2·ha-1 represented mean volume of 243 and 197 m3·ha-1,respectively. The average biomass (t·ha-1) was 237 in Ghoragali site and 186 t·ha-1 in Lehterar site, which is equal to 128 and 100 t C ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t·ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% inthe top soils. In mixed broadleaved evergreen forests a mean basal area(m2·ha-1) was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3·ha-1. The average upper and understorey biomass (t·ha-1) was 50.93 in Kherimurat site and 40.43 t·ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t C ha-1 including soil Cstocks. This study provides a protocol and valuable baseline data for monitoring biomass and carbon stocks in Pakistan’s managed and unmanaged sub-tropical forests.     

Structural development and productivity of replanted mangrove plantations in Kenya

Forest structure and productivity was investigated in a 12-year-old Rhizophora mucronata Lam. plantation at Gazi Bay, Kenya. Sampling was carried out in 22, 10 m × 10 m quadrats laid along belt transects perpendicular to the waterline. Within each quadrat all trees with stem diameter greater than 2.5 cm were identified, position marked and counted. Vegetation measurements included tree height (m), canopy cover (%) and stem diameter measured at 1.3 m above the ground (D₁₃₀); from which were derived basal area (m²/ha); stand density (stems/ha) and biomass (t/ha). Information regarding composition and distribution of juveniles was derived using linear regeneration sampling (LRS). The replanted forest had a stand density of 5132 stems/ha; with a mean canopy height and stem diameter of 8.4 ± 1.1 m (range: 3.0–11.0 m) and 6.2 ± 1.87 cm (range: 2.5–12.4 cm), respectively. The total juvenile density was 4886 saplings per hectare; 78.6% of which constituted the parental canopy. The standing biomass for the 12-year-old R. mucronata plantation was 106.7 ± 24.0 t/ha, giving a biomass accumulation rate of 8.9 t/(ha year).     

Distribution patterns of tree,understorey, and detritus biomass in coniferous and broad-leaved forests of Western Himalaya,India

Forest biomass pools are the major reservoirs of atmospheric carbon in both coniferous and broad-leaved forest ecosystems and thus play an important role in regulating the regional and global carbon cycle. In this study, we measured the biomass of trees, understorey, and detritus in temperate (coniferous and broad-leaved) forests of Kashmir Himalaya. Total ecosystem dry biomass averaged 234.2 t/ha (ranging from 99.5 to 305.2 t/ha) across all the forest stands, of which 223 t/ha (91.9–283.2 t/ha) were stored in above- and below-ground biomass of trees, 1.3 t/ha (0.18–3.3 t/ha) in understorey vegetation (shrubs and herbaceous), and 9.9 t/ha (4.8–20.9 t/ha) in detritus (including standing and fallen dead trees, and forest floor litter). Among all the forests, the highest tree, understorey, and detritus biomass were observed in mid-altitude Abies pindrow and Pinus wallichiana coniferous forests, whereas the lowest were observed in high-altitude Betula utilis broad-leaved forests. Basal area has showed significant positive relationship with biomass (R² = 0.84–0.97, P < 0.001) and density (R² = 0.49–0.87). The present study will improve our understanding of distribution of biomass (trees, understorey, and detritus) in coniferous and broad-leaved forests and can be used in forest management activities to enhance C sequestration.