Relationships of climate change and tree ring of Betula ermanii tree line forest in Changbai Mountain

Based on the tree-ring growth characteristics of Erman＇s birch （Betula ermanii charm.） and the relationships between it and climatic ）＇actors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits is that the main climatic control factor on tree-ring growth was not current growth season temperatures, as might be expected, but previous winter and current March temperature. Although the precipitation in the region was quite abundant, the tree-ring growth was still significantly correlated with the precipitation during previous winter and current spring. Additionally, climatic factors which influenced the Erman＇s birch growth were not the yearly variables, but seasonal and monthly variables. Therefore, the reported increase in yearly mean temperature and total yearly precipitation since 1980s was not responded by sustained increase in ring widths in recent decades.     

Planting six tree species on soda-saline-alkali soil

IntroductionThereareabout2,ooo,ooohm2Ofsoda-saline-alkaIisoilinSonglunpIaininHeiIongjiang(Shen1998).ltisdistributedmainlyinZhaodong,Zhaozhou,Zhaoyuan,Anda,Daqing,Duerbuteandothercountiesandcities.FormerIy,therewerenotreesonsoda-saline-alkaIisoil.CropscannotgrowonsuchsoiIs.PIantingtreesonthesesoilsmightimproveonitsquaIity(LingetaI1982).TostudypIantingonsoda-saline-aIkalisoiIhassignificanceforestablishingprotectivepIantationsystemofgrasslandandestabIishingperfectprotec-tivepIantations…     

Application of Grey System Theory to tree growth prediction

IntroductionDahurian larch plantations were planted affer the1950's in Heilongjiang Province. Some of them areless than 40 years old. There lack permanent plots oflong-term. Sometimes, statistical models for predicting tree growth are not always desirable. The GreySystem is a new branch of mathematics founded byProf. Deng Julong in 1982 (Deng 1985). In contrast tostatistic models, which need a lot of measured data,the Grey System only need a f6w data for setting upmodels. In recent years…     

Environmentally sound timber extracting techniques for small tree harvesting

Forestcontractors,loggersandengineershavebeenpayingahighattentiontotimberextractionoperationssince1990's.Sincetimber-extractingoperationproducesthehighestproportionofoperationcosts,largestareadisturbedandmostresidualstandsdamagedamongalloperationsofsmalltreeharvesting,manytechniquesweredevelopedtomeettherequirementsoftimberextractioninsmalltreeharvesting.Animalskidding13Animalskidding,oneoftimberextractionmethods,usessomespecialdevicessuchassledgesandcarriagesasshowninFig.1toreducetheresistanc…     

Filling the "vertical gap" between canopy tree species and understory shrub species:biomass allometric equations for subcanopy tree species

Subcanopy tree species are an important component of temperate secondary forests.However,their biomass equations are rarely reported,which forms a "vertical gap" between canopy tree species and understory shrub species.In this study,we destructively sampled six common subcanopy species(Syringa reticulate var.amurensis(Rupr.) Pringle,Padus racemosa(Lam.) Gilib.,Acer ginnala Maxim.,Malus baccata(Linn.) Borkh.,Rhamnus davurica Pall.,and Maackia amurensis Rupr.et Maxim.) to establish biomass equatio...     

New indices to balance α-diversity against tree size inequality

The number and composition of species in a community can be quantified with α-diversity indices,including species richness(R), Simpson’s index(D), and the Shannon–Wiener index(H’). In forest communities, there are large variations in tree size among species and individuals of the same species, which result in differences in ecological processes and ecosystem functions. However, tree size inequality(TSI) has been largely neglected in studies using the available diversity indices. The TSI in the d...     

Predicting site productivity of the timber tree Pterocarpus angolensis§

Pterocarpus angolensis is an important timber tree of the miombo woodlands of sub-Saharan Africa. The species only grows in natural mixed forests and little is known about is productivity potential. This study aimed at investigating productivity of P. angolensis on a local scale in Namibia and Angola and on a regional scale in southern Africa. The most commonly accepted productivity indicator is stem diameter increment and this was used to study productivity at a regional scale. Indicators of productivity used at the local scale were basal area, proportional basal area and site form, which were derived from 217 forest inventory plots in Namibia and Angola. The productivity measures were modelled with abiotic site factors; biotic factors were added for the local scale. Results indicated that the most consistent site factors at local and regional scale were not related to climate but to forest cover, with the species having a competitive advantage in more open forests. Mean annual diameter increment in the open forests of Namibia was 0.51 cm after 50 years. Boosted regression tree models at a local scale showed that species presence can be modelled more successfully than species basal area, proportional basal area (correlation of 0.72 vs 0.56 and 0.45, respectively) and site form. The sites with the highest productivity of P. angolensis at the local scale had a temperature seasonality below 34.5 °C, a slope of less than 1.5°, tree cover less than 20% and stand basal area higher than 9 m² ha^?1. The results can assist in establishing a site-dependent growth model for the species and direct forest and fire management towards the most productive areas.     

Quantification of tree species diversity in forest stands—model BIODIVERSS

This paper presents a method for complex evaluation and quantification of tree-layer species diversity in forest ecosystems—model BIODIVERSS. The model was constructed for the assessment of species diversity on a small-scale (forest-stand) level, but may be applied with advantage to regional and large-scale inventories. The probability of correct classification of species diversity degree is relatively high; e.g. with a sampling intensity of only 1.5%, the correctness of the classification by the model is already 90%. Model BIODIVERSS is a simple and practical tool. It can be used directly during fieldwork, since for its application only a pocket calculator is needed.     

The Crown Window — a simple device for measuring tree crowns

The paper presents a new method for assessing crown radii at different tree heights, using a simple mechanical device, the crown window. The accuracy of the crown window measuring device is evaluated using measurement data from different objects. The device is easy to manufacture and proved to be more useful than other more sophisticated techniques, such as digital photo analysis or laser based instruments in estimating crown radii and their corresponding heights with acceptable accuracy.     

Effects of the second-generation larch plantations onsoil fertility and tree growth

Larch is one of the most important plantation species in the northeast region of China. After clear cutting of larch plantations it is the urgent problem to besolved that whether the second generation is continuously plant6d, whether the soil fertility is decreasing and the plantstion is how to be managed onthe forestry produCtion. In odder tO realize the secondgenerahon Of larch plantstions and to provide thetheoretical base and the reasonable managementmeasures, we inventoried the groWth o…     

Changes in limiting resources determine spatio-temporal variability in tree–grass interactions

Changing biotic and abiotic stress mediate in plant–plant interactions resulting in positive to neutral or negative effects, and these effects can change with gradients of stress or through plant dynamics. Here we studied the variability in annual grass production and composition induced by gradients of intercepted light by trees in years of contrasting precipitation in Mediterranean holm oak open woodlands. Although trees reduce the light radiance received by the pasture community, the presence of trees generally had a positive effect on pasture production in average climatic years where soil fertility was low. However, the interaction changed with increasing abiotic water stress. In a dry year, the increase in fertility could not be utilized and the effect of the crown was neutral. The effect of shade turned out to be beneficial for growth, contrary to the situation in an average climatic year. Light insolation was positive for legume biomass. There was high variability in functional components over the course of the growing period and from 1 year to another. Under low levels of other biotic stresses such as livestock grazing or root competition, the limiting factor among light, soil moisture or soil nutrients may determine whether facilitation or competition occurs.     

Effect of three tree species on UV weathering of wood flour-HDPE composites

Eucalyptus urophylla, Acacia mangium, and Pinus caribaea are the primary species for the wood industry in Vietnam. Wood residues of these species were used to reinforce high-density polyethylene(HDPE) composites. The flexural or bending property, impact strength and surface color were evaluated after exposure to accelerated ultraviolet weathering up to 2000 h. The weathered surface was characterized by scanning electron microscopy(SEM) and Fourier transform infrared(FTIR) spectroscopy. The results indicate that A. mangium/HDPE composites had the lowest color change and least fading,and remained stable after 1500 h exposure. FTIR spectroscopy showed that the oxidation of the composites increased in parallel with duration of exposure by assessing the concentration of carbonyl groups on the surfaces. SEM showed that all three species reinforced composites exhibited similar severe cracks after 1000 h;however, at the end of the weathering test, E. urophylla and P. caribaea composites were more severely cracked than A. mangium composites. A. mangium also had the highest flexural strength, impact strength and crystallinity duringweathering. A. mangium is the most preferable among the three species to reinforce HDPE.     

Gmelina arborea– a viable species for smallholder tree farming in Indonesia?

Across Indonesia there are millions of hectares of degraded land in need of rehabilitation. There is interest at both the government and farmer level of converting some of these lands to more productive use, including growing trees. Smallholders often practice tree farming to generate income and traditionally cultivate a wide range of tree species in mixed agroforestry systems. Grown to satisfy both household needs and market demand, smallholder-produced timber might play a potentially important role in local markets. Tectona grandis, Swietenia macrophylla, and Paraserianthes falcataria are common smallholder timber species. Gmelina arborea (gmelina) is easy to cultivate and grow at the smallholder level. It has been widely grown in plantations in South and Southeast Asia, including Indonesia. However, gmelina is not yet a priority species with Indonesian smallholder farmers. Experience indicates that marketable small-diameter gmelina timbers can be produced in 7–10 years and that price compares well with that of Paraserianthes, the most widely grown short-rotation smallholder timber species in Indonesia. Most gmelina seed originates in Central Java, from where large quantities of seed are shipped annually to other parts of Indonesia. This seed is of uncertain quality, as seed sources are unidentified and seed collection guidelines are not used. It is recommended to establish smallholder plantations with seed of known quality. Gmelina holds promise as one component for a multi-species smallholder tree farming systems to produce short-rotation timbers for household use and local markets. Palabras clave: Agroforestales, Ensayos agrícolas, Producción de madera por pequeños propietarios, Rehabilitación de tierras, Selección de especies Resumen. A través de Indonesia, hay millones de hectáreas de terrenos degradados los cuales necesitan ser rehabilitados. Existe interés tanto al nivel gubernamental como al nivel de los agricultores, en convertir algunos de estos terrenos en sitios productivos, incluyendo la producción de árboles. Con frecuencia, para generar ingresos, los pequeños propietarios plantan árboles para cosecha y tradicionalmente cultivan un amplio rango de especies de árboles, en una variedad de sistemas agro-forestales. La madera de los pequeños propietarios, producida para satisfacer tanto las necesidades hogareñas como las demandas del mercado, puede jugar un papel potencialmente importante en los mercados locales. La Tectona grandis, la Swietenia macrophylla, y el Paraserianthes falcataria son especies comúnmente producidas por los agricultores. La Gmelina arborea (gmelina) es una especie de fácil cultivo y crecimiento al nivel de los pequeños propietarios, y se ha venido produciendo ampliamente en el sur, y el suroriente de Asia, incluyendo Indonesia. Sin embargo, la gmelina no es aún una especie de prioridad para los pequeños agricultores de Indonesia. La experiencia indica, que la madera de gmelina de pequeño diámetro puede salir al mercado en un período de 7–10 años y que el precio de esta madera es comparable con la madera del Paraserianthes, la cual es la especie de corta rotación más ampliamente utilizada por los pequeños propietarios en Indonesia. La mayoría de la semilla de la gmelina proviene de Java Central, de donde se envían anualmente grandes cantidades de semilla a otras partes de Indonesia. Esta semilla es de calidad incierta, ya que las fuentes de semilla no están identificadas y no se utilizan normas de colección de semillas. Se recomienda que las plantaciones de los pequeños propietarios sean establecidas con semilla de calidad conocida. La gmelina es prometedora como parte del sistema de cultivo de árboles de especies múltiples de los pequeños propietarios, para producir madera de corta rotación para ser utilizada localmente y enviada a mercados locales.