Initial Spacing: How Many Trees To Plant (original) (raw)
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Canadian Journal of Forest Research
We report on a 60-year-old red pine (Pinus resinosa Aiton) spacing trial experiment located in Ontario, Canada, that included the combinations between six initial spacings (from 1.2 to 3.0 m) and the presence or absence of a commercial thinning (CT) regime, as well as their impacts on quadratic mean diameter (QMD) and stand volume yield. The CT regime, initiated at age 30, targeted a residual basal area (BA) of 38 m2·ha−1after each of four entries. Without thinning, as initial spacing increased, QMD increased; gross and net volume production peaked in the 2.1–2.4 m spacings. With thinning, similar trends with spacing were evident for QMD, although piece sizes were larger and differences between spacings were lower. The immediate increase of mean tree size caused by tree selection explained most of the differences in QMD between thinned and unthinned plots. Thinning to a common target BA resulted in similar standing volume across spacings. Cumulative gross yield was similar between s...
Spacing rectangularity effect on the growth of loblolly pine plantations
Canadian Journal of Forest Research, 2002
The effect of spacing rectangularity on tree growth and stand development was evaluated using tree data obtained annually from a loblolly pine (Pinus taeda L.) spacing trial monitored through age 16 years. In this trial, plots with an initial planting density of 2240 trees/ha occur at slightly and highly rectangular spacings. Spacings with rectangularities 3:4 and 1:3 were used to evaluate the rectangularity effect. Survival and the development of height, diameter, volume per hectare, and basal area per hectare of loblolly pine trees were not affected by rectangularity. Diameter and height distributions were found to be a function of age but not a function of the rectangularity of initial spacing. Crown width, however, was affected by rectangularity. The crown width was larger at larger row or column distance than at smaller row or column distance, but the ratio of crown widths between and within rows was not equal to the rectangularity of the original planting spacing.
The effects of spacing and thinning on stand and tree characteristics of 38-year-old Loblolly Pine
Forest Ecology and Management, 2000
The effects of early and continuous density control on tne characteristics of mature loblolly pine (Pinus tuedu L.) were measured at age 38 and analyzed. Trees in plots planted at spacings of 1.8x 1.8, 2.4x2.4, 2.7x2.7, 3.0x3.0, and 3.7x3.,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 m2 haa'. 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. 0 2000 Elsevier Science B.V. All rights reserved. fed.us (V.C. Baldwin Jr.). and stand growth and yield and tree form in planted and natural stands of different densities (e.g. USDA, Forest Service, 1929; Mann and Dell, 1971; Burkhart et al., 19X7), information regarding the morphology and yield differences in older plantations is lacking. We analyzed standing-tree measurements and intensive felled-tree measurements (of thinned trees) at age 38 of a long-term, loblolly pine growth and yield study. Our objective was to show the effects of initial planting spacing and thinning (1) on biomass and volume 0378-l 127/00/$ -see front matter 0
Effects of genetics, management intensity, and seedling density on early stocking in loblolly pine
2015
Rapid establishment and early tree growth can be key factors in successful plantation management. This generally entails planting good quality planting stock at a seedling density appropriate for the management objectives and then managing at an appropriate intensity with a goal of fully occupying the site as quickly as possible within the context of those objectives. We established a study to examine the performance of two varietal lines of loblolly pine (Pinus taeda L.) planted at three spacings and managed at two levels of intensity. After five growing seasons, management intensity and genetic variety were both significantly affecting tree height and diameter growth. This has resulted in significant differences in stocking, with relative density (%SDImax) ranging from 4 to 31 percent. Initial tree spacing has yet to begin affecting individual tree growth, but higher relative densities in the tighter spacing suggest that these plots will soon start experiencing the effects of inte...
The establishment phase is a very critical decision-making phase in the life of a pine plantation. Key choices in site preparation intensity and type, pre-plant competition control, species selection, seedling genetic quality and size, fertilization, and first year post plant herbaceous weed control have large and long lasting effects on wood yields, rotation length, and products grown. Within a level of forest management, planting density, spacing configuration, and subsequent survival rate can affect stand access, time of canopy closure, time to first pine straw harvest, age to first thinning, number of thinnings, and product class distributions over time. Initially, higher planting densities yield more volume. Eventually, without thinning, stand volumes converge between lower and higher initial stand densities. The more intensive the management and the higher the site productivity the sooner this convergence occurs. An attractive initial spacing for slash pine (Pinus elliottii En...
Biomass partitioning in a miniature-scale loblolly pine spacing trial
Canadian Journal of Forest Research, 2009
Stand conditions influence the partitioning of biomass to stem, needle, branch, and root components. Using data from 4-to 6-year-old loblolly pine (Pinus taeda L.) trees grown in a miniature-scale spacing trial, this study determined the effect of initial spacing on the biomass partitioning of loblolly pine. Multivariate analysis of variance procedures concluded that row and column spacing did not have a significant effect on the relative amount of biomass among tree components. Root/shoot and height/diameter ratios, however, differed across densities, indicating that allometric-based partitioning tradeoffs occurred. Results from the miniature-scale trees showed trends similar to those observed with mature-sized trees at operational spatial scales. Stem and woody roots were 70% and 14% of total mass, respectively. Since these trees were physiologically young at the time of harvest, the allocation of mass to needle continued to be a priority, accounting for 10% of the total mass. Initial planting spacing did not directly affect partitioning patterns; however, allometric ratios offered some evidence that partitioning may have changed between above-and below-ground tree components. This analysis offers insight into using principles from similarity analysis to analytically relate biomass partitioning from miniature to operational spatial scales.
Effects of initial spacing on height development of loblolly pine
The relationship between dominant height and age is the base of site index, the most widely used measure of site quality. In applying the site index concept, one typically assumes that height development is not affected by stand density or thinning treatment. This assumption has been challenged by recent studies on loblolly pine. A detailed data set with initial densities ranging from 6,730 to 750 trees/ha and covering ages 1 through 25 after plantation establishment was used to study and model the effect of initial spacing on height development of loblolly pine. Dominant height was found to be dependent on initial spacing. Height-age models are proposed that take into account the effect of spacing on average and dominant height. The differences among plantation densities are evident from age 6 and are consistent to the end of the 25-year period of study. Previous studies in other conifers have reported an early advantage in terms of height growth in denser stands that tend to disappear with age, producing a crossover of the growth trajectories. No evidence of this crossover effect in height was found. FOR. SCI. 57(3):201-211.
Forest Ecology and Management, 2013
Loblolly pine (Pinus taeda) is an important timber species in the southeastern US and abroad. A better understanding of loblolly pine crown relationships with growth has implications for improving productivity estimates using process-based models or remote sensing techniques. Four study installations in the Upper Coastal Plain and Piedmont of Georgia were used to examine the effects of planting density and cultural intensity on loblolly pine stand growth and crown attributes. Treatments included six planting densities, ranging from 740 to 4440 trees ha À1 , in a split-plot design with two different levels of fertilization and competition control. The ''low intensity (LI)'' cultural treatment included relatively high nutrient inputs and early competition control. The ''high intensity (HI)'' cultural treatment included even greater nutrient inputs and complete sustained competition control. Treatment effects on stand and crown attributes were examined at age 13. Fertilization and competition control did not have a major influence on stand and crown attributes. Stands planted at lower densities resulted in significantly greater DBH and height but less standing volume per hectare, basal area per hectare, and current annual increment (CAI) volume growth compared to stands planted at higher densities. Stand-level foliar biomass, peak projected leaf area index (LAI), foliar nitrogen (N) content, specific leaf area (SLA), and intercepted photosynthetically active radiation (IPAR) were significantly greater for stands planted at higher densities, while live crown length and crown ratio were significantly greater for stands planted at the lower densities. IPAR efficiency (CAI per IPAR) was significantly affected by planting density, with values of 0.32-0.42 m 3 %IPAR À1 for 740 and 4440 trees ha À1 , respectively. At this stage of stand development, light limitations due to high stocking have a greater influence on growth than soil resource limitations for the loblolly pine plantations analyzed in this study. Higher density stands resulted in increased SLA and IPAR efficiency, supporting the idea that higher density stands utilize light more efficiently than lower density stands.
Modeling individual tree growth for juvenile loblolly pine plantations
Forest Ecology and Management, 1996
Modeling juvenile growth of loblolly pine plantations is important for a better understanding of the whole process of stand development and helping to schedule appropriate silvicultural treatments for young stands. This paper evaluates spacing treatment effects on young loblolly pine trees and presents individual tree growth models for loblolly pine plantations. Using data from spacing trials (plot size ranging from 1.22 X 1.22 to 3.66 X 3.66 m2) for loblolly pine plantations, a generalized randomized block design (GRBD) analysis was conducted to test spacing treatment and site quality effects on young tree growth. It is shown that planting density and site quality have significant influence, and spacing rectangularity is negligible. Based on the Bertalanffy differential equation and biologically reasonable assumptions regarding density and site quality effects on tree growth, a general projection model for individual tree diameter and height was developed. A stochastic model for generalizing tree height predictions within each diameter class was proposed. Models for crown ratio, and initial diameter distribution were also developed. The models were estimated with spacing trial data from young loblolly pine plantations. Validation results for these models showed that they are appropriate for predicting the juvenile growth of loblolly pine plantations where competing vegetation has been controlled in a similar manner to these spacing trials.