Bole Biomass Research Articles

Aboveground Tree Biomass for Pinus ponderosa in Northeastern California

Forest managers need accurate biomass equations to plan thinning for fuel reduction or energy production. Estimates of carbon sequestration also rely upon such equations. The current allometric equations for ponderosa pine (Pinus ponderosa) commonly employed for California forests were developed elsewhere, and are often applied without consideration potential for spatial or temporal variability. Individual-tree aboveground biomass allometric equations are presented from an analysis of 79 felled trees from four separate management units at Blacks Mountain Experimental Forest: one unthinned and three separate thinned units. A simultaneous set of allometric equations for foliage, branch and bole biomass were developed as well as branch-level equations for wood and foliage. Foliage biomass relationships varied substantially between units while branch and bole biomass estimates were more stable across a range of stand conditions. Trees of a given breast height diameter and crown ratio in thinned stands had more foliage biomass, but slightly less branch biomass than those in an unthinned stand. The observed variability in biomass relationships within Blacks Mountain Experimental Forest suggests that users should consider how well the data used to develop a selected model relate to the conditions in any given application.

Snag longevity and surface fuel accumulation following post-fire logging in a ponderosa pine dominated forest

In a study of post-fire logging effects over an 8year period at Blacks Mountain Experimental Forest, salvage logging was conducted at varying levels of intensity after a 2002 wildfire event. In a designed experiment, harvest prescriptions with snag retention levels ranging from 0% to 100% in 15 experimental units were installed. Observations of standing snags and surface fuels were made 2, 4, 6, and 8years after the fire. Fire-killed snags fell rapidly over time, leading to elevated surface fuel levels in areas where no salvage logging was done. The 1000h and larger surface fuels were strongly related with basal area retention level, with values ranging from 0–60Mgha−1 by year eight. However, when expressed as a percent of standing retained biomass, surface fuel accumulation was not related to treatment. In year 8, surface fuel was 81% of retained bole biomass. The retention of snags after this wildfire event provided snags for wildlife foraging and nesting habitat, however most of these snags were lost within 8years after the fire. White fir snags were more stable than pine and appeared to be used with greater frequency than pine for cavity excavation.

Two-stage sampling to estimate individual tree biomass

The accurate estimation of tree biomass is crucial for the efficient management of forest resources. In this study, we used a subsampling method for unbiased estimates of above-ground tree biomass. The method consists of 2 stages: the first stage consists of randomized branch sampling (RBS) and the second stage uses importance sampling (IS). RBS is used to select a path from the butt of an object branch to a terminal segment. IS is used for selecting a disk that produces unbiased estimates of the fresh biomass of tree. In this study, the subsampling method was tested on 14 black pine sample trees (Pinus nigra Arnold subsp. pallasiana (Lamb.) Holmboe) in order to estimate the trees' biomass quickly and easily. The results showed a wide range of sampling error per tree, ranging from 2.51% to 22.63%. However, the sampling error for the total biomass of the 14 trees tested was only 2.65%. The proposed 2-stage sampling method generally performed better for the bole biomass than the branch biomass. These results indicated that the proposed 2-stage sampling method is effective and might overcome many of the identified constraints in biomass estimation. It is a viable alternative to the current methods used in Turkey.

Improvement in accuracy of aboveground biomass estimation in Eucalyptus nitens plantations: Effect of bole sampling intensity and explanatory variables

Two sets of aboveground biomass equations were fitted for stem only and stem plus crown predictive variables in Eucalyptus nitens plantations in Northern Spain. A sample of 40 trees was chosen after a complete study of variation in tree height and diameter in the region. The trees were felled and the biomass was divided into the following components: wood, bark, thick branches, thin branches, twigs, leaves and dead branches along the stem. Bole biomass was estimated by systematic subsampling of one 5 cm-thick disk every 0.5 m. Such intensive subsampling enabled determination of the effect of subsampling intensity on accuracy and bias of wood estimation, considering two ratio-type estimators: stem weight to dry matter, determined by the complete weighing (CW) method (i.e. of the fresh weight of the entire stem) and volume to dry matter, determined by the partial weighing (PW) method. The changes in moisture content and basic density along the stem explained the serious risk of dry mass or weight overestimation when a systematic subsample is considered. The average basic density was usually found at a relative height of 30–35% along the stem. The default choice of the bottom disk or log as the first section resulted in overestimations for the CW method and underestimations for the PW one. The biomass equations were fitted by seemingly unrelated regression, with corrections for heteroscedasticity carried out by weighted fitting. Diameter at breast height was the best explanatory variable, and the inclusion of height did not improve the accuracy, except for wood. The inclusion of crown variables improved the predictive ability for crown fractions, increasing the accuracy for estimating thick branches (by 10.8%), twigs (by 19.1%) and leaves (by 17.3%). The biomass of each fraction decreased in the following order: wood > bark > thick branches > dead branches along the stem > leaves > thin branches > twigs. The changes in these percentages with diameter class and the predictive ability of the fitted equations were also studied.

Comparative assessment of the relationship of satellite data with the above ground biomass of Sal trees (Shorea robusta) determined from phenologically different time periods

The Above Ground Biomass (AGB) estimates of vegetation comprise both the bole biomass determined through a volumetric equation and litter biomass collected from the ground. For mature trees, the AGB estimated in phenologically different time periods is directly affected by the litter biomass since the Diameter at Breast Height (DBH) and height (H) of such trees that are used in the estimation of bole biomass would remain unchanged over a reasonable time period. In the present study, we have determined the AGB of Sal trees (Shorea robusta) in two contrasting seasons: the peak green period in October being devoid of litter on the ground and the leaf shedding period in February with abundant amount of litter present on the ground. Estimation of AGB for the month of February included the litter biomass. In contrast, the AGB for October represented only the bole biomass. AGB was estimated for ten different plots selected in the study area. The AGB estimated from ten sampling plots for each time period was regressed with the individual tree parameters such as the average DBH and height of trees measured from the corresponding plots. The regression analysis exhibited a significantly stronger relationship between the AGB and DBH for the month of October as compared to February. Furthermore, the correlation between the remotely sensed derived data and AGB was also found to be significantly higher for the month of October than February. This observation indicates that inclusion of the litter biomass in AGB will tend to decrease the regression relationship between AGB and DBH and also between the remotely sensed data and AGB. Therefore, these conclusions invite careful consideration while estimating AGB from satellite data in phenologically different time periods.

EQUAÇÕES PARA ESTIMATIVA DA BIOMASSA INDIVIDUAL DE Nectandra grandiflora Ness (CANELA-AMARELA)

Este estudo tem como objetivo testar modelos matemáticos com o fim de gerar estimativas do peso seco de cada compartimento da biomassa seca de Nectandra grandiflora, a partir de variáveis de fácil mensuração. Os dados utilizados são provenientes da Estação Experimental da UFPR em São João do Triunfo, localizada no centro-sul do estado do Paraná. Foram utilizados dados de peso seco total e parcial de 30 árvores de canela-amarela, que foram obtidos por meio de determinações diretas pelo método destrutivo. De cada árvore amostrada foram medidos também o CAP (circunferência à altura do peito), o diâmetro de copa e a altura total. Os resultados mostraram que os modelos para estimativa de peso seco de folhagem não se mostraram satisfatórios, enquanto para galhos e raízes os ajustes foram apenas razoáveis para alguns dos modelos, embora os erros padrões das estimativas tenham sido sempre superiores a 20%. Concluiu-se que as biomassas secas, total e do fuste, podem ser estimadas com qualidade, o mesmo não ocorrendo com a folhagem. Já para raízes e galhos, os ajustes podem ser estimados razoavelmente dentro de limites observados nos indicadores estatísticos R2 e erro padrão da estimativa.

Statistical models for biomass and volume of Azadirachta indica A.Juss. grown under rainfed conditions in semi-arid region of central India

Four non-linear functions, viz., Exponential, Logistic, Schumacher and Chapman-Richards were fitted for bole biomass, total wood biomass and bole volume (over bark) of Azadirachta indica. The functions were fitted using 13.5 years old trees data and explanatory variables ‘D’and ‘D2H’, where D- diameter at breast height and H- height of tree. The goodness of fitted models was judged by mean square error and adjusted R2 criteria. These models were also subjected to graphical analysis for selecting best model. In case of bole biomass and total wood biomass, the Logistic models B1 = 82.882[1 + exp (1.908-9.443 D2H)]-1 and B2 = 156.677[1 + exp (1.963-9.897 D2H)]-1; where B1- bole biomass in kg/tree, B2- total wood biomass in kg/tree; were found to be best fit. Whereas in case of bole volume, the Chapman-Richards model V= 0.99[1 – exp (-0.259 D2H)]0.969, where V- bole volume (over bark) in m3/tree, was found best fit on the basis of statistical and graphical criteria. Hence, the proposed models may be used for estimating the bole biomass, total wood biomass and bole volume (over bark) of Azadirachta indica tree in semi-arid region with reasonable accuracy.

Estimating annual bole biomass production using uncertainty analysis

Two common sampling methodologies coupled with a simple statistical model were evaluated to determine the accuracy and precision of annual bole biomass production (BBP) and inter-annual variability estimates using this type of approach. We performed an uncertainty analysis using Monte Carlo methods in conjunction with radial growth core data from trees in three Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) dominated sites (young, mature, and old-growth) in the western Cascades of Oregon. A model based on the mean and standard deviation of annual radial growth from sampled trees was used with and without stratification by tree size to predict radial growth for non-sampled trees. Sample sizes of 64–128 trees per stand were required to achieve accuracy and precision within ±10%. Without stratification the model underestimated annual BBP (Mg ha −1 year −1) in all three age classes by up to 28%, and inter-annual variability by as much as 26%. Applying stratification increased accuracy of estimates at least twofold, and precision of estimates improved by 3–10%, resulting in decreased sample size requirements. The coefficient of variation of error of estimates was half that of inter-annual variability over the study period. Thus, this approach can be used to examine patterns of inter-annual variability of BBP in response to changing climate and land use patterns.

Thinning and Prescribed Fire Effects on Forest Floor Fuels in the East Side Sierra Nevada Pine Type

Forest thinning accomplished with cut-to-length and whole-tree harvesting systems combined with prescribed underburning were assessed for their impacts on downed and dead fuel loading of all timelag categories in eastern Sierra Nevada Jeffrey pine (Pinus jeffreyi Grev. & Balf.). Cut-to-length harvesting resulted in an approximate doubling of total fuel loads with the greatest increases occurring in the 100-hr and 1000-hr categories, while changes associated with whole tree harvesting were marginal to the extent that overall posttreatment loading differed little between whole-tree and unfhinned treatments. Following the thinning operations, 1 + 10-hr and total fuel accumulations in the cut-to-lengfh treatment and 1000-hr fuels in the whole-tree treatment were positively correlated with harvested basal area and harvested foliage, branch, bole, and total tree biomass in simple regression models. Subsequent consumption during underburning eliminated 1 + 10-hr and 100-hr fuel additions from cut-to-lengfh harvesting along with a portion of the natural loading in these categories but was much less effective in reducing the 1000-hr fuels generated by this harvesting. Consumption of 1 + 10-hr, 100-hr, and total fuels in all thinning treatments was positively correlated with the amounts present within each category before underburning. Results reported here provide insight into fuel load modifications resulting from field practices that are being increasingly integrated into comprehensive management efforts to improve forest health and fire resilience in the western United States.

TREE MORTALITY DURING EARLY FOREST DEVELOPMENT: A LONG-TERM STUDY OF RATES, CAUSES, AND CONSEQUENCES

Tree mortality is a critical but understudied process in coniferous forest development. Current successional models assume that mortality during early forest development is dominated by density-dependent processes, but few long-term studies exist to test this assumption. We examined changes in forest structure and patterns of tree mortality 14–38 years (1979–2001) after clear-cut logging of two experimental watersheds in the western Cascade Range of Oregon, USA. We sampled 193 permanent plots (250 m2) six times generating 75126 data records and 7146 incidents of mortality. Mean density peaked at >3000 stems/ha (≥1.4 m tall) after 22–25 years; bole biomass increased continuously to >100 Mg/ha. At final sampling, stem density varied by two orders of magnitude and biomass by a factor of 10 among sample plots. Suppression mortality occurred in >80% of plots and was >2.5 times as frequent as mechanical damage (uprooting, stem snap, and crushing). However, biomass lost to mortality via mechanical damage was nearly four times that lost to suppression, a result of episodic storms that created windthrow patches, with some plots losing 30–50% of biomass. Total annual mortality increased from 1.0% to 5.3% of stems over the study period and was highly variable among species. Although mortality rates were highest for sprouting hardwoods (reaching 9.7% in Cornus nuttallii), biomass of most hardwood species increased through canopy closure as dominant stems achieved large sizes. Shade-tolerant conifers (Tsuga heterophylla and Thuja plicata), typically assumed to be absent or to play a minor role in early forest development, accounted for 26% of stems after 38 years. In regression tree models, environmental attributes of plots had limited ability to predict mortality. Instead, stem density prior to canopy closure was the strongest predictor of cumulative mortality (either suppression or mechanical damage). Our long-term studies suggest that current models of early forest development are overly simplistic, particularly in their treatment of mortality. Although suppression was the dominant demographic process, mechanical damage yielded greater loss of biomass and greater structural heterogeneity through creation of windthrow gaps. Thus, gap-forming processes that operate late in succession and contribute to structural complexity in old-growth forests can also occur early in stand development.

Biomass equations and carbon content of aboveground leafless biomass of hybrid poplar in Coastal British Columbia

Hybrid poplar plantations offer opportunities for enhancing carbon sinks, but accurate assignment of carbon credits requires accurate estimation of the amount of carbon stored in poplar biomass. Here we present individual-tree bole and branch biomass equations derived for Populus trichocarpa Torr. and Gray × P. deltoides Marsh. hybrids from plantations in coastal British Columbia, Canada. Trees ranged in age from 4 to 13 years old and were planted at a density of 1111 stems ha −1. Equations were applied to similar short-rotation intensive-culture plantations near or at rotation age to derive estimates of aboveground leafless biomass production and amount of carbon sequestered. After 12 years, predicted aboveground leafless biomass accumulation ranged from 9.2 to 13.6 Mg ha −1 year −1; predicted bole biomass accumulation ranged from 7.5 to 11.3 Mg ha −1 year −1. Total carbon in aboveground leafless biomass at age 12 ranged from 51.2 to 75.7 Mg ha −1. Three of the stands reached 14 years of age prior to harvest. Predicted carbon content of aboveground leafless biomass at 14 years of age ranged from 73.7 to 88.7 Mg ha −1.

Aboveground biomass partitioning in loblolly pine silvopastoral stands: Spatial configuration and pruning effects

Patterns of biomass partitioning have been extensively studied in loblolly pine ( Pinus taeda L.) plantations and natural stands, but not in silvopastoral practices, which are being promoted in southern United States. We conducted aboveground biomass harvests in 18-year-old loblolly pine growing in single-, double-, and quadruple-row configurations at 2.1 m between trees in the row, and initial densities of 308, 568, and 932 trees ha −1. In the double- and quadruple-row configurations, rows were 2.4 m apart while alleys were 14.6 m wide in all configurations. Trees were felled from single, double (east and west orientations) and, the exterior east and one of the interior (trees identified as QR2) quadruple rows, and separated into bole, branches, twigs (<2 cm in diameter), and foliage. In total, 60 trees within the 25–29 cm DBH class were sampled (five configurations × three trees per row × two pruning regimes × two replicates). Averaged across pruning regimes, absolute total aboveground biomass per tree ranged from 366 kg in single-row trees to 231 kg in QR2-trees while bole biomass varied from 185 kg in single-row trees to 143 kg in QR2-trees. Configuration affected relative biomass partitioning to boles ( P < 0.05), which ranged, on an average, from 60% of total tree biomass in quadruple rows to 52% in single rows, branch ( P < 0.05), which varied from 30% in single rows to 24% in quadruple rows, and foliage ( P < 0.001), which ranged from 12% in single rows to 8% in quadruple rows. Bole DBH and available ground space per tree (as covariates) did not affect biomass partitioning as neither did pruning, although pruning markedly improved log quality. Basal areas in single-, double-, and quadruple-row configurations in the silvopasture were 11, 19, and 34% greater than the projected basal areas for adjacent loblolly pine plots with similar stand density.

Carbon stock estimates for sugi and hinoki forests in Japan

Forest inventory data are widely used for broad-scale quantification of forest carbon budgets. Such data usually represent forest wood volume (m 3 ha −1), which needs to be converted to biomass carbon value (Mg C ha −1) for carbon stock estimates. Our main objective is to estimate the carbon stock for all sugi ( Cryptomeria japonica D. Don) and hinoki ( Chamaecyparis obtusa Endl.) plantations in Japan on the basis of age-class-based forestry statistics. To achieve this purpose, we estimated regional wood volume accumulation and biomass allocation over time for sugi and hinoki forests to calculate and map the carbon stock in all sugi and hinoki plantations in Japan on the basis of forestry statistics. Hinoki forests showed smaller accumulation of volume than sugi forests from ca. 25 years old to maturity; the accumulation of wood volume per hectare at 80 years old was <600 m 3 ha −1 for hinoki and >600 m 3 ha −1 for sugi. Patterns of biomass allocation to forest components varied by forest type; the proportion of branch biomass in 0–20-year-old hinoki forests is 5–10% larger than that of sugi; the proportion of stem biomass in the same age range is 5–10% smaller than that of sugi; the ratio of roots was approximately constant as its average value, 20.4% for sugi and 22.7% for hinoki. The ratios of total biomass to bole biomass (i.e., expansion factor (EF), Mg total biomass Mg −1 bole biomass) decreased with increasing age, and became nearly constant after 30 years old for sugi and hinoki. The mean EFs were the same for the two forest types, with a value of 1.72 Mg Mg −1. Our results suggest that sugi and hinoki plantations in Japan, respectively, store 346.4×10 6 and 139.2×10 6 Mg of carbon, with an area-weighted mean of 76.81 and 58.01 Mg C ha −1. High amounts of carbon stock in both sugi and hinoki are located in the southwestern part of Japan.

Production of Mass and Nutrient Content of Decaying Boles in Mature Deciduous Forest in Kwangnung Experimental Forest Station, Korea

In order to elucidate the characteristics of standing crop biomass, production and nutrient content of dead bole in mature ecosystem, we surveyed the dynamics of decaying bole of old-aged deciduous forest in 1993 and 2002 in Kwangnung Experimetal Forest Station. In addition, we and estimated annual bole production, water content, wood density and nutrient content and compared the results with that of temperate ecosystem. Total dead wood biomass was estimated to be 5.6ton/ha in 1993 and 17.6 ton/ha in 2002. Standing dead tree accounted for a total of 1.1 ton/ha in 1993 and 4.8 ton/ha in 2002, which was 20% and 27 of the sum of dead bole mass in 1993 and 2002, respectively. Annual production of bole biomass was 1.3 ton/ha/yr. These values fall into the low range of dead wood biomass for the mature temperate ecosystems. Tree species composing standing bole was mainly Quercus and Carpinus trees. This bole species composition resembles alive species composition of this forest. Water content of bole increased as positive logarithmically, but wood density of bole decreased as negative exponentially along with the progress of decay. N, P, Ca and Mg concentrations in decaying boles generally increased with decay, except for K. Annual nutrient input via dead bole is 1.6 kg/ha/yr for N, 0.04 kg/ha/yr for P, 1.0 kg/ha/yr for K, 1.7 kg/ha/yr for Ca and 0.3 kg/ha/yr for Mg, respectively.

Trends in bole biomass accumulation, net primary production and tree mortality in Pseudotsuga menziesii forests of contrasting age.

Although it is generally accepted that the rate of accumulation of biomass declines as forests age, little is known about the relative contributions to this decline of changes in net primary production (NPP) and tree mortality. We used 10-15 years of observations of permanent plots in three small watersheds in and near the H.J. Andrews Experimental Forest, Oregon, to examine these issues. The three watersheds are of similar elevation and potential productivity and support young (29 years at last measurement), mature (approximately 100 years) and old (approximately 400 years) forest dominated by Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. Accumulation of tree bole biomass was greatest in the young stand, reaching approximately 7 Mg ha-1 year-1 in the last measurement interval. Bole biomass accumulation was relatively constant (approximately 4-5 Mg ha-1 year-1) in the mature stand, and there was no net accumulation of bole biomass in the old-forest stand. The NPP of boles increased with time in the young stand, from approximately 3 to approximately 7 Mg ha-1 year-1, but was nearly constant in the mature and old-forest stands, at approximately 6 and 3-4 Mg ha-1 year-1, respectively. Mortality increased slowly in the young stand (from < 0.1 to 0.3 Mg ha-1 year-1), but fluctuated between 1-2 and 2-6 Mg ha-1 year-1 in the mature and old-forest stands, respectively. Thus, declining biomass accumulation with stand age reflects, in approximately equal amounts, both decreasing NPP and increasing mortality.

Toppling in juvenile pines: A comparison of the root system characteristics of direct-sown seedlings, and bare-root seedlings and cuttings

Three-year radiata pine (Pinus radiata D. Don) direct-sown seedlings, bare-root seedlings and cuttings were excavated by hand from a planting trial in Taranaki, New Zealand. Eighteen trees were sampled, six of each plant type. Root system characteristics were compared by investigating differences in above- and below-ground biomass, root length, root size and root biomass distribution. No significant differences were found between plant types in total below-ground biomass, root:shoot ratio, tap root or sinker root biomass. Significant differences between plant types were found for total above-ground, branch, foliage, root bole and lateral root biomass. Additional significant differences were encountered for total root length, tap root and lateral root length. The study found the observed wind-firmness of direct-sown seedlings was unlikely to be because of the size or development of the tap root systems, the degree of symmetrical distribution of their lateral roots or higher root:shoot ratios, but could be associated with the greater proportion of total root biomass allocated to their near-stem lateral roots. It is proposed that the increase in biomass allocated to the near-stem portion of the root system, particularly on the leeward side of a tree, can be considered as an early indicator of emerging tree stability. A field-based method is suggested as a way of obtaining a measure of root anchorage. If plant types are to be developed for greater resistance to toppling, the results from this study would suggest that root stiffness, i.e. less root flexibility, should be a priority consideration in any selection or breeding programme.

Eucalypt forest structure and synthetic aperture radar backscatter: a theoretical analysis

Eucalypt forest attributes describing structure are required for a range of management and inventory programs. The characterization of vegetation structure can be a laborious task and so managers and researchers are seeking alternatives through the use of remote sensing. Forest structure and the distribution of biomass through the forest canopy has a significant effect on radar backscatter and, in many cases, is the overwhelming variable in determining the type and quantity of radar backscatter observed in forest environments. In southern Tasmania a combination of field-based inventory plots and forest type maps were accessed to condense large variations in forest structure into five archetypical structural forest types. We then utilized a forest backscatter model to simulate the backscatter response of these five forest structural types for a range of radar wavelengths and polarizations. Good correlative relationships were obtained between backscatter and forest structure. There was a particularly good relationship between synthetic aperture radar to variations in allocation of biomass to stems, branches, and leaves. These individual and grouped attributes in eucalypt forests appear to influence radar backscatter enough to develop predictive relationships between backscatter and forest structure. Strong correlations were observed with radar P- and C-band wavelengths with foliage and bole biomass and between the ratio of L to C with foliage and branch allocations. Within Australian wet sclerophyll forests, where the biomass is typically very high, the true capacity and applicability of radar imagery may not be in direct biomass estimation but rather in the capacity of radar data to stratify forest stands based on structural variation.

The effects of spacing and thinning on stand and tree characteristics of 38-year-old Loblolly Pine

The effects of early and continuous density control on the characteristics of mature loblolly pine ( Pinus taeda L.) were measured at age 38 and analyzed. Trees in plots planted at spacings of 1.8×1.8, 2.4×2.4, 2.7×2.7, 3.0×3.0, and 3.7×3.7 m were either left unthinned or thinned every 5 years beginning at age 18, to residual basal areas of 27.5, 23.0, 18.4, and 13.8 m 2 ha −1. Trees thinned from plot buffer zones at age 38 were selected to represent a final harvest cross-section of each treatment for evaluation of bole form, component biomass, and crown architecture. Volume and biomass of cut trees from all thinnings were included with the age 38 data for stand level yield comparisons. Results show thinning effects were generally more pronounced than spacing effects. Trees of the same diameter at breast height and total height from heavily thinned stands had more cylindrical lower boles, more upper stem taper, longer crowns with more and larger branches, more total foliage, and hence more biomass than trees from unthinned or lightly thinned stands. All levels of thinning increased the yield of the stand in terms of foliage and branch biomass, while only light or moderate thinning increased bole biomass and volume yields. The magnitude of these differences are presented.

Growth and ecological impacts of traditional agroforestry tree species in Central Himalaya, India

A number of multipurpose tree species are conserved as scattered trees in settled farms on terraced slopes by the traditional farmers in Central Himalaya, India. Knowledge on growth rates and ecological impacts of these tree species is limited. Ten locally valued multipurpose tree species, viz., Albizzia lebbek, Alnus nepalensis, Boehmeria rugulosa, Celtis australis, Dalbergia sissoo, Ficus glomerata, Grewia optiva, Prunus cerasoides, Pyrus pashia and Sapium sebiferum, were established as mixed plantations at a degraded community forest land site and an abandoned agricultural land site in a village at 1200 m altitude in District Chamoli, India. At the abandoned agricultural land site, annual food crops were grown, along with planted trees, providing supplemental irrigation and organic manure following traditional farming practices. Survival, height, stem circumference, crown depth and width, number of branches, above-ground biomass and soil physico-chemical characteristics were monitored up to five years of plantation growth. Above-ground tree biomass accumulation at the abandoned agricultural land site was 3.9 t ha−1 yr−1 compared with 1.1 t ha−1 yr−1at the degraded forest land site. B. rugulosa, C. australis, F. glomerata, G. optiva, P. cerasoides and S. sebiferum showed more prominent differences in growth at the two sites compared with A. lebbek, A. nepalensis, D. sissoo and P. pashia. A. nepalensis and D. sissoo showed best growth performance at both the sites. A significant improvement in soil physico-chemical characteristics was observed after five years at both of the sites. Carbon sequestration in soil was higher than that in bole biomass.

Allometric equations for two South American conifers: Test of a non-destructive method

Non-destructive biomass estimation for protected tree species is necessary to understand their population dynamics and the ecological factors affecting species scarcity. We present a method for estimating aboveground biomass of bole, branches and foliage, using data obtained by climbing live trees to collect limited samples and measurements. This method was applied to 26 individuals of Fitzroya cupressoides (Mol.) Johnston, a protected Chilean conifer, and to 12 individuals of a second, morphologically similar, but unprotected species, Pilgerodendron uviferum (D. Don.) Florı́n. Trees were climbed, basal diameter of all branches >1 cm were recorded and four branches per tree were removed for further measurement. The sampled branches were used to develop allometric equations predicting branch, twig and foliar biomass from branch basal diameter. These equations were used to generate whole tree canopy biomass estimates based on climber's measurements of branch basal diameter. Bole biomass was estimated from serial measurements of height, diameter and wood density. Whole tree canopy and bole biomass estimates were then used to develop allometric equations predicting wood and foliar biomass from diameter at breast height. Five of the P. uviferum trees were felled and weighed by conventional methods, and the data used to evaluate error in the non-destructive technique. Although the technique was labor intensive, it was found to yield mean estimates for canopy components that are expected to be within 10% of the true mean for large populations of trees (watershed level studies). Accurate estimation of individual trees may be less reliable, as the amount of dispersion about some of the regressions was quite high (>20%).