Commercial Tree Species Research Articles

Assessing the geochemical balance of managed boreal forests

Abstract A sustainable forest management system requires that a balance must be reached between ecosystem nutrient losses and gains in the course of a rotation. In order to determine the influence of stand characteristics (species composition, density, site potential productivity), method of forest harvesting (stem-only versus whole-tree) as well as rotation length on nutrient losses induced by biomass harvesting, a geochemical balance (nutrient inputs minus outputs) was computed from published information and forest inventory databases for the southern portion of the boreal forest of Quebec. Losses were compared with potential nutrient gains that varied according to soil types. We provided a tool for assessing the risk of having a negative nutrient budget (outputs>inputs) that forest managers can use with information that is already available to them. This exercise was conducted for five commercial tree species, namely paper birch (Betula papyrifera Marsh.), aspen (Populus tremuloides Michx.), balsam fir (Abies balsamea (L.) Mill.), jack pine (Pinus banksiana Lamb.), and black spruce (Picea mariana (Mill.) B.S.P.), grouped into four site indexes and three stand density classes. Strong differences in nutrient exportation in biomass appeared between stands of different compositions as well as between stands of the same species but of different classes of productivity or density. The most nutrient-demanding tree species were trembling aspen and balsam fir. As expected, whole-tree harvesting caused a greater drain on nutrient reserves than stem-only harvesting, but this effect varied strongly with tree species and was greatest for balsam fir and lowest for jack pine. Harvesting the forest before or after the age of financial maturity, which might be desirable under some circumstances, generally created a lesser nutrient drain but this was at the expense of biomass production. Aspen was an exception to this rule showing a greater nutrient drain for stands harvested prior to the age of financial maturity. Implications for the development of indicators of sustainable forestry and for future research are discussed.

Post-fire tree regeneration in lowland Bolivia: implications for fire management

Abstract Tree regeneration was compared in burned and unburned portions of a tropical dry forest (1110 mm ppt/year) and a tropical humid forest (1542 mm ppt/year) in southeastern Bolivia. Both forests burned 5 years prior to our study, and both forests were also lightly selectively logged ( intensity m 3 /ha ) —the dry forest during the 1970 and 1980s and the humid forest just prior to the wildfire. The objective of this study was to compare abundance, size, and mode (seedling or resprout) of tree regeneration in burned and unburned areas of these forests, focusing on the most common canopy tree species and the commercial timber species at each site. Regeneration of 13 species of trees was quantified in the humid forest and 12 species in the dry forest. Tree regeneration 20 cm tall was more abundant in the dry forest ( x =1807 stems/ha ) than in the wet forest (x=490 stems/ha ) . In both forests, resprouts were generally larger but less abundant than seedlings. In the dry forest, regeneration of the following commercial tree species was significantly more abundant in the burned areas: Cedrela fissilis, Anadenanthera colubrina, Astronium urundueva, and Centrolobium microchaete. However, Acosmium cardenasii, a canopy tree species not marketed for timber in Bolivia, represented the majority of regeneration (63%) in the dry forest and was equally abundant in burned and unburned areas (∼1100 stems/ha). In the humid forest, only one timber species, Aspidosperma rigidum, was more abundant in burned than unburned areas (51 vs. 0 stems/ha, respectively). Another timber species that is rarely harvested in the region, Pseudolmedia laevis, was significantly less abundant in the burned than unburned area (22 vs. 173 stems/ha, respectively). The results of this study suggest that controlled burning could increase the abundance of timber tree regeneration at the dry forest site and to a lesser extent at the humid forest site. No data were collected to assess the likelihood that this increased density of regeneration will result in increased harvestable timber. However, local forest management institutions do not presently appear capable or motivated to conduct fire management—whether for enhancing timber regeneration or for limiting the damage caused by accidental wildfires.

Genetic variation among and within provenances and families of Eucalyptus grandis W. Hill and E. globulus Labill. subsp. globulus seedlings in response to salinity and waterlogging

The economics of tree growing on salt-affected land or with saline water irrigation will be considerably improved if sources of more salt-tolerant seed of commercial tree species can be identified and deployed. This paper deals with three experiments to evaluate variation in salt and waterlogging tolerance among and within provenances and families of Eucalyptus grandis W. Hill (flooded gum) and E. globulus Labill. subsp . globulus (Tasmanian blue gum), both commercially important timber species in southern Australia, but with an overall low to moderate tolerance to salt and combined salt and waterlogging. In experiments 1 (five families of E. grandis from each of seven provenances) and 2 (four families of E. globulus from each of six provenances), four treatments—control (C), salt (S; 75 and 150 mol m −3), waterlogging (W) and combined salt and waterlogging (SW)—were applied in factorial combinations to 14-week-old ( E. grandis) and 10-week-old ( E. globulus) seedlings in sand-filled pots. In experiment 3, the above treatments were applied to 9-week-old ( E. globulus; four families) and 12-week-old ( E. grandis; four families) seedlings cultured as above, but in this case, salt concentrations were incrementally increased from 150 to 450 mol m −3, and a larger number of seedlings used than for the previous experiments. In all experiments, the salt mix comprised NaCl, MgSO 4, MgCl 2 and CaCl 2 with molar elemental ratios of 12:2:1 of Na:Mg:Ca and 8:1 of Cl:SO 4. For both species in experiments 1 and 2, height and shoot dry weight was reduced much more by combined salt and waterlogging than by either treatment alone. Shoot dry weights for S, W and SW treatments were reduced by 49, 77 and 80%, respectively, for E. grandis and by 28, 70 and 73%, respectively, for E. globulus. Large differences in growth were found among families within provenances and among provenances, irrespective of treatment. Although there were marked differences in growth among provenances and families-within-provenances in response to salt, waterlogging and combined salt and waterlogging, these differences were non-significant when ln-transformed data were analysed, except among E. globulus provenances in response to waterlogging ( p<0.05). Estimates of narrow-sense heritability ( h 2) for shoot dry weight in the presence and absence of salt and waterlogging ranged from 0.35 to 0.92. Family differences were found for leaf Cl and Mg concentrations in relation to applied salt. Marked variation in seedling health and height growth was found between individual seedlings within families of both species in experiment 3. Prospects for improving tolerance to salt and combined salt and waterlogging are discussed.

Predição da estrutura diamétrica de espécies comerciais de terra firme da amazônia por meio de matriz de transição.

Esta pesquisa se originou de uma base de dados de dois inventários a 100% realizados em 1984 e 2000 sobre uma mesma área de 576 ha de floresta tropical primária, localizada na Floresta Nacional do Tapajós, Belterra, Pará. A pesquisa objetivou avaliar a evolução da estrutura diamétrica de seis espécies comerciais de terra firme da Amazônia no período 1984-2000 e projetá-la para 2016, utilizando-se de matriz de transição. Nos dois inventários, as CAP foram medidas com fita métrica, sendo que em 1984, as alturas comerciais foram medidas com o hipsômetro de Weiss e, em 2000, estimadas com o uso de varas; o DAP mínimo em 1984 foi de 55 cm para todas as espécies e, em 2000, foi adotado o DAP mínimo de 35 cm. A construção da matriz de transição foi precedida de análise exploratória de dados (AED), em que se utilizou o box plot (caixa-de-bigodes) na detecção de outliers (observações discrepantes) e o gráfico stem-and-leaf (tronco-e-folhas) para filtrar as observações extremas. A análise da estrutura diamétrica mostrou que a evolução do DAP, observada no período 1984-2000, apresentou comportamento diferenciado por espécie, embora mantendo a forma básica da distribuição típica de cada espécie, enquanto a projeção da estrutura diamétrica para 2016, usando matriz de transição, manteve-se com a tendência esperada, com base nas taxas de crescimento expressas pelas raízes latentes da matriz de transição o que demonstra estar compatível com o perfil da estrutura diamétrica observada em 2000.

Mechanical cleaning and prescribed burning for recruiting commercial tree regeneration in a Bolivian dry forest

A critical component of sustainable forest management is the regeneration of commercially valuable tree species. Mechanical cleaning with machetes and chainsaws, prescribed burning, and a combination of both treatments were applied to recently-created logging gaps in a Bolivian dry forest to evaluate their impact on the natural regeneration of commercial tree species and on control of competing vegetation. The three treatments and an untreated control were applied to logging gaps during the dry season of 1998 and replicated ten times. Eight months following burning, the density of commercial tree regeneration in gaps did not differ statistically among treatments. Relative height growth of total commercial regeneration also did not differ among treatments, although it did vary by species. Reduction in competing vegetation following the application of site preparation treatments was significantly higher, but competing plant cover was beginning to converge among treatments after eight months. Despite better control of competing vegetation, early recruitment and growth responses to burning and cleaning of vegetation in logging gaps do not appear to justify application of these treatments in this forest, especially considering their high costs.

The Amazon flood plain forest tree Maquira coriacea (Karsten) C.C. Berg: aspects of ecology and management

Maquira coriacea is a commercial tree species growing throughout the Amazon flood plain forests. Densities up to 14/ha of individuals, ≥10 cm diameter at breast height (DBH) were observed, corresponding to a basal area of 2 m 2/ha and a volume of 38 m 3/ha. The primary period of fruiting coincided with the annual flooding, but fruits were also produced in other parts of the year. Seedlings with densities up to 150/m 2 were concentrated around mother trees, and the stocks fluctuated much over the year due to mortality caused by flooding and wilting in dry periods. Growth data mainly from nine 1 ha permanent sample plots were used to develop models of the height–diameter relationship and diameter increment. These relationships indicated that the optimal felling limit for maximum volume production was 120–130 cm DBH, which can be obtained in 150–260 years. Since seed production has been observed in much smaller individuals, such diameter limits should not be detrimental to regeneration.

Growth of Three Pine Species after Eleven Years on Reclaimed Minesoils In Virginia

Abstract A reforestation experiment was established to test the growth of three pine species on two different surface-mined sites in the Appalachian coalfields of southwest Virginia. One site was mined just prior to enactment of the 1977 Surface Mining Control and Reclamation Act (SMCRA), and one site was mined and reclaimed to its approximate original contour in accordance with post-SMCRA regulations. Three pine species (Pinus taeda, P. virginiana, and P. strobus) were planted on each site in 1981. A fertilization and an herbaceous weed control treatment were tested. Half the plots were fertilized with a 21 g fertilizer tablet at time of planting and a broadcast application of 50 kg/ha N as ammonium nitrate prior to the fourth growing season. Each plot was split to accommodate an herbaceous weed control treatment during the first 3 yr. After 11 yr, all three tree species grew very well on the prelaw bench site, but were less productive on the postlaw AOC site. The fastest growing species was loblolly pine, which averaged 22 ft tall. Aggressive herbaceous ground covers commonly established on surface-mined land to reduce erosion were successfully controlled by herbicides, resulting in a significant improvement in survival and growth for all tree species. Fertilization as used in this study had little effect on growth and was not as beneficial for tree establishment as the herbicide treatment. The performance of these commercial tree species in this study demonstrates that good forest management opportunities exist for the owners of surface-mined land. North. J. Appl. For. 17(3):95–99.

Regeneration of timber species following selection logging in a Bolivian tropical dry forest

The establishment of commercial tree regeneration is currently a focus for concern regarding the sustainability of logging in the tropical forests of Bolivia. This study compared the density, species composition, and growth of sawtimber species seedling and sapling regeneration 14 months following selection logging. Areas sampled included logging gaps, logging roads, skid trails, and log landings. Areas not disturbed by logging were also sampled as controls. The abundance and composition of competing vegetation in tree regeneration plots was also measured. The highest density and greatest initial height growth rates of tree regeneration were observed on areas with the greatest amount of soil disturbance, including log landings and logging roads. This trend was largely due to the higher densities of two common, light-seeded, shade-intolerant species, Anadenanthera colubrina and Astronium urundeuva. Despite having higher light availability than other sites, tree regeneration of all species was poor in logging gaps. Logging gaps were quickly colonized by competing vegetation, particularly lianas, where they had a percent cover 2.5 times that in undisturbed sites. Regeneration of some commercial species in these forests appears to respond more favorably to disturbances that exceed those provided by single tree selection logging. Despite the better initial establishment and growth of a few species on areas with soil disturbance caused by logging, the lack of regeneration of other commercial tree species and the increasing colonization of all sites by competing plants indicate the need for post-harvest competition control treatments to ensure vigorous commercial species regeneration that will contribute to the sustainable management of this forest.

Bark thickness equations for five commercial tree species in regrowth forests of Northern New South Wales

Summary Bark thickness at any point along the stem of eucalypt regrowth tree species is related to over-bark diameter at that point, height above ground at point of measurement along the stem, total tree height and breast height diameter over-bark. Equations have been derived for predicting bark thickness as a function of these variables and of over-bark diameter along the stem. Using these equations eliminates the need for routine bark-gauge measurements and their associated measurement errors and helps to accelerate the derivation of more precise stem volume functions. When used in conjunction with a tree or log taper function, the equations can provide estimates of the volume of bark resulting from harvesting and available for utilisation. Using data collected for taper and volume functions development for the Resource and Management Evaluation System at State Forests of New South Wales, nine different bark thickness equations were fitted for Eucalyptus pilularis, E. obliqua, E. andrewsii, E. saligna, and Corymbia maculata growing in northern coastal areas of New South Wales. Comparisons using fit statistics for all species and test statistics based an independent data set for E. pilularis, show that some equations were systematically biased for all species and it was recommended that they should not be used. The equation developed by Cao and Pepper (1986), labelled equation [8], was found to be the most consistent for all species.

Early understory successional changes following clearcutting in the balsam fir-yellow birch forest

Community response to disturbance is influenced by species life history and the nature of disturbance. In this study we investigated the effects of clearcutting on the early successional changes of an understory species community in the balsam fir-yellow birch forest type of the Lower St. Lawrence Region of Québec, Canada. Clearcuts of 5, 10 and 20 years were sampled along with mature stands. In each of these communities, ten circular quadrats of 400 m2 were established where the percent cover of herb, fern, and shrub species was estimated. Along a 150-m transect starting in the middle of each quadrat, the seedling density of commercial tree species was measured in ten 4-m2 plots. Detrended Correspondence Analysis (DCA; cover values) was used to describe the early successional changes in the understory community and a Correspondence Analysis (CA) was used with presence/absence data to evaluate the compositional differences. The results revealed a time gradient associated with understory community changes, in which the first 10 years of successional changes are characterized by the dominance of shade intolerant species. A decrease in the floristic heterogeneity was associated with clearcut logging. Small herb species with a shallow root system were most affected by logging. For commercial tree seedlings, the changes following clearcutting were characterized by a decrease over time in the density and stocking of shade intolerant and mid-tolerant species (principally white and yellow birches). In the older clearcuts, sugar maple appeared to be the dominant commercial species in the seedling understory. The results suggested that clearcut logging in the balsam fir-yellow birch forest type may contribute to rapidly shifting the seedling understory composition towards dominance by shade tolerant species. This situation may be related to the dominance of mountain maple in the understory of old clearcuts that contribute to reducing the available light in the understory, thus increasing mortality of shade intolerant seedling species. Clearcutting may also have deleterious effects on some understory herb species that need particular conditions before re-establishing in a site. Logging tends to reduce micro-site heterogeneity over large extended areas—a situation that may preclude the re-establishment of some late successional herb species.

Predicting the natural occurrence of blackbutt and Gympie messmate in southeast Queensland

Summary Australian State and Commonwealth Governments are committed to a rapid expansion of forest plantations through the 2020 Vision and post-Regional Forest Agreement industry development packages. Part of this expansion is expected to be met by an increased uptake of farm forestry. However, lack of reliable information about the plantation capability of native Australian hardwoods and a suitable framework for delivering such advice are some of the impediments to widespread uptake of farm forestry options. While many native tree species have potential for use in plantations, it maybe decades before selection trials deliver consistent advice about their capability and site suitability. It is therefore important to use all available sources of information and tools to help alleviate the knowledge gap. This paper describes an application of generalised linear modelling for predicting the natural occurrence and performance of commercial tree species in native forest, as a source of background information for evaluating plantation potential. A comprehensive agency dataset for the distribution of commercial hardwoods in southeast Queensland native forests is used to derive logistic regression models and ecological response functions for the relationship with key environmental factors (water, temperature, nutrients, light). The resulting spatial predictions and indicative responses will be used to develop our understanding of likely performance in plantations. Case studies for two species blackbutt (Eucalyptus pilularis) and Gympie messmate (E. cloeziana) are presented.

Early response of selected tree species to liberation thinning in a young secondary forest in Northeastern Costa Rica

Short-term growth responses in individuals of four commercial tree species ( Laetia procera, Simarouba amara, Tapirira guianensis, and Vochysia ferruginea) were evaluated one and two years after `liberation thinning' in a young (4.5-year-old), dense secondary forest stand located in an agricultural settlement in wet, Northeastern Costa Rica. Liberation thinning involved manual elimination (either by cutting or stem girdling) of the adjacent `ring' of competitors in order to release future crop trees (median diameter: 8 cm DBH), selected on the basis of stem and crown form. The application of liberation thinning significantly increased diameter growth of future crop trees with respect to unmanipulated counterparts. Young stands in the region may be attractive systems for simple silvicultural manipulations due to rapid growth responsiveness, facilitated by manageable tree size. Detailed observations on stand development and patterns of crown stratification in coexisting tree species in other dense secondary stands in the area seems warranted in order to refine silvicultural options aimed at increasing tree diameter growth.

A method for classifying commercial tree species of an uneven-aged mixed species tropical forest for growth and yield model construction

The sparse distribution of timber species in the tropical rainforest has been a major obstacle in the construction of timber growth and yield models for forest management planning. Models for individual species usually have biased parameter estimates because of the sparse representation of those species ( Vanclay, 1991). We present a technique for pooling species with similar growth characteristics into groups to minimize the level of bias in the estimation of model parameters. Principal component, canonical discriminant, and approximate covariance estimation for clustering procedures ( Milligan and Cooper, 1985) were used to transform and improve the sphericity and separation of multivariate diameter increment data. The k-th nearest neighbor clustering technique ( Wong and Lane, 1983) was used to evaluate the most likely number of species clusters within the population covered by the data. The average linkage, complete linkage, and Ward's minimum variance hierarchical clustering procedures ( Milligan, 1981) were separately applied to the transformed data to identify the characteristics of inherent structures as the basis for classifying similar species into groups. An objective reclassification criterion was used to evaluate the performance of the three clustering methods. Optimal species groupings were attained, with 86.3% cluster recovery, by applying Ward's minimum variance method to data transformed by the canonical discriminant procedure. Consequently, six species growth classes were formed on the basis of the similarities of species growth increment patterns. This objective procedure is guaranteed to produce optimal species groups, with minimal internal variations, suitable for developing unbiased estimates of growth model parameters. The analytic procedure should be applicable to most tropical forest ecological types similar to the moist semi-deciduous forest.

Thirty Year History of Even-Aged Management

Forests of Turkey were severely degraded and depleted as a result of mismanagement particularly during the application of uneven-aged management periods. With the beginning of a national call for planning, all forests except fir-dominated stands are planned for management under even-aged management methods. This paper explains and discusses the results of application of even-aged management on Calabrian pine forests and Eastern spruce forests in Turkey. As shown in 1973 with the first timber inventory, the implementation of even-aged management failed in the first planning period to create an optimal forest structure. It was observed, however, that even-aged management is beginning to accomplish an optimal forest structure in Calabrian pine forests with successful silvicultural treatments. In contrast, implementations of the even-aged management method on spruce forests was found unsuccessful so far. It is concluded that the method would be implementable in spruce-dominated forests and the other light-demanding commercial tree species as well if the silvicultural plans are prepared carefully based on site classification, and if the welfare system of the forest villagers in Eastern Black Sea region is improved.

The agroforest alternative to Imperata grasslands: when smallholder agriculture and forestry reach sustainability

Basic prerequisites for sustainable reforestation of Imperata grasslands in Southeast Asia are presented. A theoretical forest is designed according to these prerequisites. Composed of basic units managed by local smallholders, the forest is composed of two sets of commercial tree species suited to local conditions, one set providing regular cash income and the other providing seasonal or irregular cash income. Such composition ensures economic and ecological viability of the forest in the long run, provided that clear tenurial right on the basic units are recognized. Guidelines for a transition from Imperata grasslands to forest are presented, underlining the importance of relying on natural succession processes. The theoretical forest is identified as an agroforest, a diverse forest rebuilt and managed by farmers, providing forest and agricultural products for both cash income and household consumption. Agroforests have been developed for decades by indigenous farmers in some regions of Southeast Asia. Examples from Indonesia are presented to support the theoretical analysis. They show that the agroforest alternative is a valuable unifying concept for reforestation of Imperata grasslands, for a sustainable upland agriculture, and more generally for an equitable environmentally and economically sound development of rural areas in the humid tropics. sound development of rural areas in the humid tropics.

First-Year Results of Partial Overstory Removal and Direct Seeding of Mahogany (Swietenia macrophylla) in Quintana Roo, Mexico

Mahogany (Swietenia macrophylla King) is the single most important commercial tree species in the forests of the state of Quintana Roo, Mexico. Mahogany regeneration has been associated with natural disturbances that increase understory light levels. A study to analyze the effect of overstory removal on seed germination and early seedling survival and growth of mahogany was conducted. Twenty-five 0.2 ha plots were treated to create different levels of overstory removal and then seeded. Two seeding methods were used, dibbling and dropping. Dropping was used to simulate the way that seeding occurs in nature. Understory light levels were measured after the overstory removal was done. A year after applying the treatments, seed germination and seedling survival were not affected by the understory light levels created by the overstory removal. It is expected that over the next several years seedling survival and growth will be more affected by understory light levels. Seedling establishment by dibbling and dropping gave similar results. There was a high correlation (r = 0.95) between the percent of overstory removal and understory light levels.

Potential Shifts in Optimum Growth Areas of Selected Commercial Tree Species and Subtropical Crops in Southern Africa Due to Global Warming

The area under agricultural production in southern Africa is declining as a result of industrial expansion, mining as well as formal and informal urbanization. Simultaneously, the increasing demand for timber products will necessitate a doubling of the present area under commercial afforestation in South Africa over the next 30 years. Potentially afforestable areas, however, frequently occur in the same climatic belts as certain subtropical fruit crops. Given the climatic constraints for optimum growth of commercially afforestable timber species and subtropical horticultural crops, that southern Africa is a largely semi-arid region, the fact that the areal extent of land available for agriculture is shrinking, together with the uncertainties and possible threats linked with anticipated global climate change, the identification of land areas suitable for future expansion of plantations and subtropical crops requires careful assessment. The spatial distributions of areas suited climatically to optimum growth of two commercial tree species, Eucalyptus grandis and Pinus patula, and two subtropical crops, avocado and pecan nut, were mapped for southern Africa using a climate threshold approach in conjunction with detailed gridded climate information bases, for both the present climate and for a possible future climate scenario. Results indicate that the possible impacts of a future temperature increase on the spatial distributions of optimum growth areas is species dependent, favouring E. grandis, avocado and pecan nut, but not P. patula. According to the climatic threshold model used, the timber species and horticultural crops considered produced a westward shift to 'new' climatically suitable areas in the future. The results also indicate that climate change resulting from the augmented greenhouse effect may benefit the horticultural industry to a greater extent than the timber industry. Hence, competition for land suitable for future expansion of certain commercial tree species and subtropical crops may become an important consideration in the future.

Cottonwood Site-Index Growth Curves

Cottonwood Site-Index Growth Curves

Effects of partial overstory removal on the natural regeneration of a tropical forest in Quintana Roo, Mexico

In a tropical, semi-evergreen forest in Quintana Roo, Mexico, a study was conducted to observe the effects of partial overstory removal (creation of multiple gaps) on natural regeneration, with special attention to commercially valuable tree species. Five 0.5-ha plots were subjected to different levels of overstory removal of 0%, 8%, 28%, 45% and 55%. The regeneration population 3 years after overstory removal was similar in density and composition to the population before overstory removal except for an unidentified liana that was not found in 1986 but was moderately abundant in 1989. Regeneration of commercial tree species (tolerant and intolerant), noncommercial tree species, and nontree species was compared with the residual basal area and percentage of basal area removed. Frequency of intolerant commercial species increased as residual basal area decreased. Frequency of tolerant commercial species was not affected by residual basal area or percentage of basal area reduced.

Estimating stump volume, stump inside bark diameter and diameter at breast height from stump measurements

Equations were derived for estimating stump volume, stump inside bark diameter at any given height from ground and diameter at breast height from measured stump height and stump inside bark diameter. The equations were tested on 33 British Columbia commercial tree species groups and the results of four species groups are presented in this paper. This prediction system will play an important role in "waste" or "residue" surveys in British Columbia and in reconstructing the initial stand conditions by estimating diameter at breast height.