Increasing Tree Diameter Research Articles

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.

Produtividade e custos do processador trabalhando em povoamentos de Eucalyptus grandis Hill ex Maiden.

No presente trabalho foi realizado um estudo de tempos com o objetivo de ajustar equações para estimar o tempo das atividades, a produtividade, o custo operacional e da produção do processador utilizado em um sistema de colheita de madeira de povoamentos de Eucalyptus grandis Hill ex Maiden, em topografia plana, no Estado da Bahia. O ciclo operacional do processador consistiu no tempo gasto para processar uma árvore e foi dividido em etapas as quais foram cronometradas, usando a metodologia dos tempos individuais. A unidade amostral foi constituída do ciclo operacional da máquina. A análise estatística baseou-se em estudo de regressão, sendo utilizado o procedimento de modelagem de regressão "stepwise". Com as equações ajustadas, foi possível estimar a produtividade da máquina em função do diâmetro das árvores. Nas condições do estudo, considerando uma eficiência operacional de 70%, a produtividade do processador foi de 25,8 m³cc/h, o custo operacional 47,90 US$/h e o custo de produção de 1,86 US$/m³cc. Com base nos resultados obtidos, pode-se concluir que: o tempo de processamento das árvores varia diretamente com o aumento do diâmetro; o tempo de preparação, ao contrário do tempo de processamento, possui uma baixa correlação com o diâmetro das árvores; a produtividade do processador é diretamente proporcional ao aumento do diâmetro das árvores, quando expressa em volume, e inversamente proporcional, quando expressa em número de árvores; o custo por metro cúbico de madeira processada com processador, varia numa relação inversa ao aumento do diâmetro; do custo operacional do processador, o custo fixo é o de maior proporção, seguido do custo variável, administrativo e da mão-de-obra; e, o custo de produção do processador diminui em forma exponencial com o aumento do diâmetro das árvores.

Ten-Year Growth Response of Young Douglas-Fir to Variable Density Varnishleaf Ceanothus and Herb Competition

Abstract The effect of different densities of varnishleaf ceanothus (Ceanothus velutinus var. laevigatus) and herbaceous vegetation control on stem diameter, height, and volume of plantation Douglas-fir (Pseudotsuga menziesii vat. menziesii) seedlings was examined during the 10 yr following planting. Initial densities of ceanothus ranged between 0 and 15,000 seedlings/ha and were obtained by interplanting ceanothus germinants or chemical thinning after clearcutting and broadcast-burning. Herbaceous vegetation control was achieved by a single application of glyphosate following planting, with shrub seedlings covered. Ceanothus density in the range of 0 to 6,750 plants/ha did not have an effect on Douglas-fir diameter, height, or volume at age 10; however, Douglas-fir growth was significantly decreased when ceanothus densities reached 15,000 plants/ha. Ten years after planting, Douglas-fir volume in the treatments with 6,750 ceanothus/ha or less was 1.7 times greater than that in the 15,000 ceanothus/ha treatment. On the other hand, removal of herbaceous vegetation after planting significantly increased tree diameter, height, and volume, regardless of ceanothus density. Even 10 yr after the application of the treatment, trees without early herb competition grew faster and had mean dbh, height, and volume that were 1.02 cm, 0.55 m, and 12.98 dm³/tree greater respectively than those with herbs. Thus, a treatment at plantation establishment to control herbaceous vegetation and to reduce ceanothus density to less than 7,000 plants/ha will ensure an increase in growth and stocking for at least 10 yr. West. J. Appl. For. 14(4):208-213.

Habitat preference of Great Argus Pheasant (Argusianus argus) in Kayan Mentarang National Park, East Kalimantan, Indonesia

Habitat preference and abundance of the Great Argus Pheasant was studied over a ten week period in the lowland forests of the Kayan Mentarang National Park, in the remote interior of Indonesian Borneo. Repeat line transect surveys, counting the number of vocalising males, were conducted in four different habitat types. Argus Pheasants were found to be most common in primary forest, and progressively less common in old and young secondary forests. Numbers of calling males were lowest in riverine forest. Argus Pheasant densities were positively correlated with a number of transect characteristics, viz. increasing tree diameter, tree height, height of the first bough and canopy cover, and with increasing remoteness. Dancing grounds were invariably located on ridges. The conservation status of the species on Borneo is briefly discussed. The Great Argus Pheasant is still widespread but thinly spread. The rapid rate of lowland forest clearance, fragmentation of once continuous habitat and increasing hunting pressure owing to increasing accessibility may become serious threats in the near future.

Black stem galls on aspen and their relationship to decay by Phellinustremulae

Efficient use of trembling aspen (Populustremuloides Michx.) is often limited by the presence of extensive decay and stain. Aspen trees with black stem galls of unknown cause reportedly have less advanced decay caused by the fungus Phellinustremulae (Bond.) Bond. & Boriss. than do adjacent trees without galls. Nine field sites having large numbers of galled aspen were surveyed for the presence of P. tremulae conks. Logistic regression showed that the odds of a gall tree having at least one conk was 44% of that for trees without galls, and that the occurrence of conks varied among sites and increased with increasing tree diameter. Inclusion of black galls in models used to predict decay might result in greater accuracy on sites where these galls are prevalent. Black galls may also be potential sources of biological control agents against decay-causing organisms in aspen.

Nine‐year Response of Thinned Slash Pine to Nitrogen, Phosphorus, and Potassium

AbstractDiagnostic procedures are needed for determining response of slash pine (Pinus elliottii Elngelm. var. elliottii) plantations on productive sites to N, P, and K fertilizer late in the rotation. A 25‐yr‐old slash pine plantation (site index = 21 m at 25 yr) in southwest Louisiana was thinned to a residual basal area of 18 m2 ha−1 and fertilized at rates of 0 to 448 kg N ha−1, 0 to 171 kg P ha−1, and 0 and 56 kg K ha−1 at selected levels of N and P. Separate experiments were established to determine response of stands and individual dominant and codominant trees to added nutrients. During 9 yr after application, N fertilizer stimulated diameter but not height or volume growth of stands. The effect of N on diameter growth decreased with increasing tree diameter at breast height (dbh) at age 25. Nitrogen had no significant effect on diameter, height, or volume growth of individual dominant or codominant trees. Phosphorus fertilizer significantly increased diameter, height, and volume growth of stands and individual trees. Regression analyses showed that diameter growth culminated with 110 kg added P ha−1 and volume growth culminated with 132 kg added P ha−1. Height growth increased lineally over the range of 0 to 71 kg added P ha−1. In otherwise comparable treatments, individual trees that were fertilized with 56 kg K ha−1 grew faster in diameter, height, and volume than those receiving none. Currently available diagnostic procedures would have identified the plantation as one that should respond to P and K fertilizer, but not to N.

Mortality, foliage loss, and possum browsing in southern rata (Metrosideros umbellata) in Westland, New Zealand

Abstract Foliage loss and possum browsing were scored separately on 1475 southern rata trees and seedlings in three neighbouring study areas in central Westland which had different histories of possum occupation. As the time of possum occupation increased, foliage loss from individual trees and the numbers of trees showing such losses increased sharply in most stands. Dead and dying trees (>75% foliage loss) were scattered in a salt-and-pepper pattern among healthier trees. Basal area of dead and dying trees constituted from 1.5% (5 years' possum colonisation) to 32% (20 years' possum occupation) of the total. Foliage loss occurred over all altitudes and sites sampled, but in one area foliage loss on sites with exposed physiography or with seral vegetation was significantly greater than on other sites. In all areas foliage loss increased with increasing tree diameter and was least from small rata trees in even-sized stands. Foliage loss was also greater in the canopy than in the sub-canopy. Possum browsin...

WITHIN-TREE DISTRIBUTION OF THE PUPAE OF THANASIMUS DUBIUS (COLEOPTERA: CLERIDAE), A PREDATOR OF THE SOUTHERN PINE BEETLE (COLEOPTERA: SCOLYTIDAE)

AbstractRegression models of the form lnY = b0 + b1ln(X−c) + b2X are presented that describe the within-tree distribution of the pupae of Thanasimus dubius (F.), a clerid predator of the southern pine beetle, Dendroctonus frontalis Zimm. More T. dubius pupae/100 cm2 of bark area were found in loblolly pine, Pinus taeda L., than in shortleaf pine, P. echinata Miller, and the number increased with increasing tree diameter class. Peak densities were found at a height of 1–4 m.