Basal Area Growth Rates Research Articles

Forest dynamics in flood plain forests in the Peruvian Amazon: effects of disturbance and implications for management

Forest dynamics were studied from 1993 to 1997 for individuals ≥10 cm DBH in nine 1 ha permanent sample plots. They were established in natural flood plain forests located on the lower Ucayali river in the Peruvian Amazon. After inventories of three plots in each of three forest types, a light and a heavy felling treatment were applied to each of the two plots, while a third plot was kept untreated. Average annual stem mortality and recruitment rates in the untreated plots were among the highest observed in neotropical rain forests: mortality 2.2–3.2% per year, recruitment 3.0–4.6% per year. Dead individuals deviated significantly from random dispersion towards clumping. The average annual basal area growth was around 1 m 2/ha per year, corresponding to average annual basal area growth rates of 3.5–3.8% per year in the untreated plots. No decrease in basal area growth was observed even in the treated plots where annual basal area mortality rates up to 41% during the first year were observed. The average diameter growth increased from 4.0–4.5 mm per year in the untreated plots to 5.3–6.8 mm per year in the treated plots. The stocking of commercial timber species was high with basal areas of 2.6–10.0 m 2/ha and volumes of 59–240 m 3/ha. The corresponding growth of basal area and volume of commercial timber species were also considerable, reaching values of 0.1–0.3 m 2/ha per year and 2–9 m 3/ha per year, respectively. These attributes suggested that forest management for timber production in these forests can be flexible and provide relatively high yields on a sustained basis. It appeared that management interventions can be carried out within the range of naturally occurring perturbations, although it should be noticed that only limited proportions of each habitat are disturbed at a time by nature. The patchy occurrence of habitats may provide logistic problems to management.

Above- and below-ground effects of aspen clonal regeneration and succession to conifers

Above- and below-ground characteristics were measured and compared for six sets of paired trembling aspen (Populus tremuloides Michx.) clones on the Fishlake National Forest in central Utah. Three self-regenerating clones were compared with three non-regenerating clones and three pure aspen stands were compared with three mixed aspen-conifer stands. Regenerating clones had dense understories of younger aspen stems, which were not present in non-regenerating clones. Regenerating clones also had greater numbers of roots and greater total root surface area than non-regenerating clones. Aboveground biomass and growth of the aspen in mixed stands was less than that of pure stands. A corresponding difference in aspen root mass was not apparent, indicating that the decline of aspen in mixed stands had not yet affected the root system. Conifer height and basal area growth rates were clearly greater than those of aspen, suggesting that aspen will eventually disappear from these forests in the absence of stand-reinitiating disturbances.

Annual rainfall, topoedaphic heterogeneity and growth of an arid land tree (Prosopis glandulosa)

Basal area growth rates for Prosopis glandulosa were quantified for contrasting landscape elements in a subtropical savanna. We hypothesized that growth rates of P. glandulosa plants (1) are a function of seasonal or annual rainfall; and (2) vary with patch type and in the rank order observed for large trees. Prosopis glandulosa growth was responsive to changes in rainfall (−0·974 cm2year−1in a dry year; 9·108 in a wet year), but correlations with rainfall were low. Growth of trees in contrasting patches was not consistently different, suggesting that contrasts in tree sizes across the landscape reflect differences in establishment dates rather than differences in growth rates.

Above- and below-ground effects of aspen clonal regeneration and succession to conifers

Above- and below-ground characteristics were measured and compared for six sets of paired trembling aspen (Populus tremuloides Michx.) clones on the Fishlake National Forest in central Utah. Three self-regenerating clones were compared with three non-regenerating clones and three pure aspen stands were compared with three mixed aspen-conifer stands. Regenerating clones had dense understories of younger aspen stems, which were not present in non-regenerating clones. Regenerating clones also had greater numbers of roots and greater total root surface area than non-regenerating clones. Aboveground biomass and growth of the aspen in mixed stands was less than that of pure stands. A corresponding difference in aspen root mass was not apparent, indicating that the decline of aspen in mixed stands had not yet affected the root system. Conifer height and basal area growth rates were clearly greater than those of aspen, suggesting that aspen will eventually disappear from these forests in the absence of stand-rein...

The effect of soil nutrition, soil acidity and drought on northern red oak ( Quercus rubra L.) growth and nutrition on Pennsylvania sites with high and low red oak mortality

Unexplained mortality of northern red oak ( Quercus rubra L.) has occurred on the Laurel Hill in southwestern Pennsylvania. We attempted to characterize this mortality and determine its relationship to soil acidity, soil nutrient status and droughts. Three blocks with high and low mortality of northern red oak were selected. Basal area increment, terminal elongation and leaf mass were measured along with soil chemistry. Basal area growth patterns were compared to historic drought records. Both living and standing dead trees on high mortality plots had been responsive to most of these droughts. After 2 years of droughts in the 1960s, basal area growth rate of trees on high mortality plots did not recover. In addition, the standing dead trees on high mortality plots were historically a less vigorous subset. After this mortality, the living trees did not respond with increased growth due to thinning of competitors. Basal area growth on low mortality plots did recover after these same droughts and mortality was limited. In addition, the trees on the high mortality plots showed foliar deficiency of K and low levels of Ca while trees on the low mortality plots did not. Furthermore, the A- and B- horizons of the soils on the high mortality plots had lower levels of soil bases, higher levels of available Al and lower Ca/Al ratios. The results of this study suggest that nutrient deficiency and associated Al toxicity may be causing stress for northern red oaks and is related to the mortality and reduced growth of northern red oak in this region.

Tree-Growth and Understory Responses to Low-Severity Prescribed Burning in Thinned Pinus ponderosa Forests of Central Oregon

Abstract The growth of ponderosa pine and associated understory vegetation was evaluated for a 6 yr period following spring underburning of surface fuels. Underburn and control (unburned) plots were paired at 15 replicate sites in pole-sized ponderosa pine forests of central Oregon. The burns were generally low in severity, as noted by low 0 horizon mass reduction (24%) and tree mortality (6%). A small but significant decline in basal area and volume growth rates of surviving trees was found in the 6 yr following underburning. The reduction in tree growth was related to a combination of crown length reduction, 0 horizon reduction, and site productivity. More productive stands had the highest proportional reduction in growth due to burning. By comparison, site conditions including stand density, initial basal area, elevation, parent material, and soil fertility were not related to the observed growth reduction. Understory vegetation showed a mixed response to burning. Shrub cover, dominated by Purshia tridentata, declined significantly following burning and remained well below preburn levels for the length of the study, even though one-fourth of all burned Purshia plants successfully resprouted. Total herbaceous vegetation cover and production were unaffected by burning, while species diversity increased slightly. With the exception of the decline in Purshia cover, the results indicate that low-severity prescribed burning has a relatively minor impact on tree-growth and understory response in thinned ponderosa pine stands. For. Sci. 46(2):258-268.

Basal area growth curves for Pinus patula in two areas of the Calamuchita Valley, Córdoba, Argentina

This study was carried out in the Calamuchita Valley, in West Central Córdoba, Argentina. Two stands of Pinus patula were chosen, one in each of two different areas: Yacanto de Calamuchita and Rı́o de los Sauces. The objectives of the study were: 1. to develop basal area (BA) mean annual increment (MAI) and current annual increment (CAI) curves for P. patula in two areas of the Valle de Calamuchita; 2. to estimate the timing of intermediate and final cuts in P. patula plantations; 3. to evaluate P. patula BA growth rate vs. other pine species that grow in the region; and 4. to identify the best growing species for each area. Thirty trees were randomly selected in each stand. An increment core was taken from each sampled tree from bark to bark through the pith. Growth rings were measured and BA-MAI and BA-CAI were calculated. Growth curves were fitted for each stand and intersection points between the MAI and CAI curves were found. Regression analysis was performed for BA-CAI vs. time up to the age of 10 years in both areas. P. patula performance was compared to that of P. elliottii, P. taeda and P. radiata growing in the same areas. It is concluded that: 1. The proper time for the first commercial thinning is about 10–12 years, just before the BA-CAI curve declines. 2. The biological rotation age is expected to occur no sooner than Year 17 in this region. 3. P. patula can perform better than P. elliottii, P. taeda and P. radiata during the first 10 years, depending on site quality and seed genetic quality.

Restoring Aristida stricta to Pinus palustris Ecosystems on the Atlantic Coastal Plain, U.S.A.

Abstract Aristida stricta (wiregrass), a perennial bunchgrass, quickly accumulates dead leaves, which along with the shed needles of Pinus palustris (longleaf pine) provide the fuel for frequent surface fires. Thus, historically, wiregrass played a key role in many longleaf communities where it significantly influenced the natural fire regime and thereby the composition of the plant community. Reestablishment of wiregrass is, therefore, critical to restoring the native understory of Atlantic Coastal Plain longleaf pine ecosystems. This study measured the effects of different site preparations and fertilizer application on the survival and growth of wiregrass seedlings. Two‐month–old seedlings were underplanted in existing longleaf pine stands on dry Lakeland soils at the Savannah River Site in South Carolina. Survival was acceptable at 51% after four years, although reduced owing to drought and small seedling size. Survival and growth could both be increased by using older seedlings with an initial height of at least 6 cm. Wiregrass leaves grew quite rapidly and attained an average length of 48 cm in four years on control plots. Basal area growth rate was greater than expected, averaging 40% on control treatments and 55% on cultivated and fertilized plots. If growth rates during the first four seasons continue, wiregrass will attain mature size on cultivated and fertilized plots at six years, while non‐fertilized control plots will take eight years. A planting density of one seedling per m2 is recommended to provide sufficient wiregrass foliar cover to influence fire regimes in a reasonable length of time (i.e., 5–7 years).

First‐year growth response of trees in an intact forest exposed to elevated CO2

SummaryAlthough elevated atmospheric CO2 has been shown to increase growth of tree seedlings and saplings, the response of intact forest ecosystems and established trees is unclear. We report results from the first large‐scale experimental system designed to study the effects of elevated CO2 on an intact forest with the full complement of species interactions and environmental stresses. During the first year of exposure to ^ 1.5 Ë ambient CO2, canopy loblolly pine (Pinus taeda, L.) trees increased basal area growth rate by 24% but understorey trees of loblolly pine, sweetgum (Liquidambar styraciflua L.), and red maple (Acer rubrum L.) did not respond. Winged elm (Ulmus alata Michx.) had a marginally significant increase in growth rate (P = 0.069). These data suggest that this ecosystem has the capacity to respond immediately to a step increase in atmospheric CO2; however, as exposure time increases, nutrient limitations may reduce this initial growth stimulation.

Effects of Crown Release on Basal Area Growth Rates of Some Broad-Leaved Tree Species with Different Shade-Tolerance

We compare three or four years effects of crown release on stem growth rates among four deciduous broad-leaved tree species,Fagus crenata, Quercus crispula, Magnolia obovata andAcer mono, in an even-aged coppice forest, central Japan. The crown release significantly improved relative growth rates for basal-area (RGRBA) of the four species. However the effects of neighboring gap area (GAPA) on the RGRBA differed among the species. The effects were significant forQ. crispula andM. obovata, indicating that growth rates of these two species increase with intensity of the crown release. In contrast, the RGRBA ofF. crenata andA. mono were not correlated with the GAPA, suggesting that their growth rates are unrelated to the intensity. We considered that such differences among species were closely related to their photosynthetic characteristics of light use; less-tolerant species (Q. crispula andM. obovata) exhibit greater growth rates relative to the intensity of crown release than tolerant species (F. crenata andA. mono). Based on these results, we proposed implications for thinning practices in mixed forests of species with different shade-tolerance.

A model of the growth of juvenile radiata pine in the Central North Island of New Zealand: links with older models and rotation-length analyses of the effects of site preparation

Data from 27 site preparation experiments were used to construct a model that predicts growth, survival and size class distributions of radiata pine with respect to altitude, weed control, cultivation, fertilisation, and initial stocking during the first five years after planting. Only stand values, however, are used in this paper. The question of linking the model with existing growth and yield models for older crops is discussed, and a theoretical structure is proposed that clarifies assumptions required if the models are jointly used to evaluate the worth of establishment practices throughout complete crop rotations. It was found that the initial growth model generally predicted similar basal area growth rates to those of the Pumice Plateau Model (PPM88), a growth model for older crops, in age ranges where the two models overlapped, but some of the assumptions required for rotation-length analyses need further testing. Measurements over 8 years in a designed experiment examining alternative site preparation strategies showed that PPM88 was insensitive to the effects of site preparation in predicting growth that occurred after the establishment phase.

Relationships among crown condition, growth, and stand nutrition in seven northern Vermont sugarbushes

We compared growth with soil and foliar elemental composition in seven stands of sugar maple (Acersaccharum Marsh.) in northern Vermont characterized by high or low incidence of crown dieback over the period 1989–1992. In stands with low-quality crown conditions, such as elevated crown dieback, long-term basal area growth rates were approximately half of those in stands with higher crown quality. Average annual basal area growth was 17.5 cm2 for dominant trees in these stands during the period 1953–1992 compared with 32.3 cm2 for trees in higher quality stands. The occurrence of elevated crown dieback was apparently unrelated to stand characteristics such as stand age, basal area, stem density, elevation, or aspect among the stands sampled. Stands with elevated crown dieback were found on soils characterized by low pH ( <4.0), low base cation pools (particularly Ca and Mg), and higher Al in soil surface horizons than higher quality stands. Over 4 years, sugar maple stands with elevated crown dieback exhibited significantly lower (P < 0.01) foliar Ca concentrations and somewhat lower foliar N and Mg than higher quality stands, while soil and foliar K were similar in both dieback classes. Among survey plots sampled in 1989, soil pH and Ca were strongly correlated with foliar Ca and K (P < 0.001). Soil pH, soil Ca, and foliar Ca were also strongly correlated with the level of crown dieback among plots and stands (P < 0.0001). Our results indicate that podzolic soils in northern Vermont may present marginal conditions for sugar maple growth in terms of soil pH and soil Ca availability, but that P and K pools appear to be sufficient for growth. While a lack of historical data prevents identification of long-term trends in nutrient availability in these soils, factors promoting losses of base cations from acidic, base-cation-poor Podzols may also exacerbate foliar nutrient deficiencies and thus affect the crown condition of sugarbushes in northern Vermont.

Productivity and growth efficiency in sugar maple forests

Sugar maple ( Acer saccharum Marsh.)-dominated northern hardwood forests were examined at four locations along an acid deposition and climatic gradient in the Great Lakes region of the USA. The study sites were matched in terms of physiography, soils, stand history, and vegetative characteristics. Measurements of basal area and biomass growth were made for the 1988–1991 growing seasons. There were no significant differences in either basal area of biomass increment among the four sites over the 4 year period. There was a great deal of year-to-year variability with relative basal area growth rates ranging from as low as 0.2% to as high as 2.4% on a single site in successive years. Growth efficiency measures reflected this variability with as much as an 800% difference between successive years on a single site. When coupled with year-to-year variability of up to 34% in leaf area related to heavy seed years and defoliation, this indicates that growth efficiency and leaf area measures are not consistent indicators of aboveground productivity for tolerant deciduous species, especially if derived from short-term measurements or temporary plots.

Dynamics of stem growth of Pinus radiata as affected by water and nitrogen supply

Changes in tree stem diameter were measured every 2 weeks on sample trees, and at intervals of 3 months on all trees, as part of a major field study investigating the impact of irrigation and fertilisation on growth of 10- to 14-year-old Pinus radiata stands near Canberra, in the Australian Capital Territory. Annual basal area growth rates varied from 2.3 m 2 ha −1 (untreated stands in dry years) to 7.2 m 2 ha −1 (irrigated and fertilised stands). The effect on patterns of growth and total increment of a range of environmental and stand parameters, including water and nutrient availability, temperature and canopy characteristics, were examined. Water and N availability interacted positively to increase growth. In the absence of fertilisation, irrigation increased growth by about 60%. The response to N fertilisation varied from zero during drough years to 200–300% when water was plentiful. Indices of either water or N availability, when used alone, were not well correlated with growth increments. However, the water stress integral ( S ψ a temporal integration of the effects of both water and N availability on pre-dawn needle water potentials), as well correlated ( r 2=0.91, P>0.001) with annual basal area increments, as were combinations of indices of water and N availability. Growth in winter was low but stands with adequate water and nutrients were able to maintain slow growth through most winters. On the other hand, stands sufferring either water or nutrients stress failed to grow at all in winter. Available water extended the period during which growth was possible whereas improved N availability effected by magnitude of growth but only when water was available.

Crown and basal area relationships of open-grown southern pines for modeling competition and growth

Data were collected on open-grown loblolly pine (Pinustaeda L.), longleaf pine (Pinuspalustris Mill.), and shortleaf pine (Pinusechinata Mill.) and analyzed to provide predictive equations of crown width and maximum potential basal area growth for crown competition and growth and yield models. The measurements were taken on 115 open-grown loblolly pine trees and 76 shortleaf pines in southeastern Arkansas. The longleaf pine data consisted of 81 open-grown trees from southern Alabama, Georgia, and Florida. A circle and an ellipse were tested as geometric models of the vertically projected crown. No significant differences between the tree shapes were found based on analyses of length and azimuth of the largest crown diameter, and the circle was chosen as an appropriate model. This indicated that only the distance between trees, not their orientation to one another, need be included in models of crown competition based on crown contact. Predictive equations of mean crown width based on diameter at breast height were fitted for each species for use in models of crown competition. A Chapman–Richards growth rate function with an intercept term was fit to periodic annual inside-bark basal area growth based on initial inside-bark basal area to provide empirical estimates of maximum basal area growth rates for growth and yield modeling of the given species. Additionally, equations to predict double bark thickness as a function of diameter at breast height were fit for each species to facilitate the use of the equations with outside-bark measurements of diameter.

Growth Model Predictions as Affected by Alternative Sampling-Unit Designs

Abstract This study analyzed the effect on growth-model predictions of introducing differential design error to predictor variables that are influenced by the sampling-unit design, such as basal area per acre. Computer simulations of five forest stands were generated from random spatial distributions and field data coveting a range of stand conditions. Two variable-radius cluster designs and four sizes of fixed-radius circular plots were used to sample the generated stands. Sample data were used to predict single-period gross basal area growth rates in both a single-tree and a whole-stand growth model. The sampling-unit design used to develop each model was defined as the standard error-free method of measuring the predictor variables. For both models, the average of gross basal-area growth rate predictions from 50 samples of each alternative sampling-unit design were not significantly different from the standard design. However, using a different sampling-unit design may produce large differences in individual predictions, particularly when small sampling units are used for application of models developed using relatively large sampling units. Such differences may affect decisions about treatment of a stand and could complicate the validation of a growth-and-yield model. For. Sci. 37(6):1641-1655.

Changing Stand Structure and Regional Growth Reductions in Georgia's Natural Pine Stands

Abstract Forest Inventory and Analysis (FIA) data indicate reductions in the growth of naturally regenerated pines in Georgia between the two latest measurement periods (1961-72 vs. 1972-82). Analysis of Covariance was used to adjust stand-level basal area growth rates for differences between periods in stand age, stand density, site index, mortality, and hardwood competition. The adjusted mean growth of pines during the later period declined by 19% for natural loblolly, 28% for natural shortleaf, and 28% for natural slash pine stands. The factor(s) causing the reductions remain unidentified, but differences in stand structure are not likely responsible. For. Sci. 37(2):703-717.

Litterfall in a secondary forest with special reference to the relationships between leaf‐fall rate, basal area and relative growth rate on a species basis

AbstractTotal basal area (BA), mean relative growth rate of individual basal area (RGRbam), annual leaf‐fall rate (L), and number of trees (N) on a species basis were measured in a secondary forest mixed with evergreen and deciduous trees in the warm‐temperate zone of Japan. Every species had a characteristic tree size and composed the tree and the shrub layers. The layer for each species, and the tree size of the species were represented by the species mean basal area per tree (BA/N or bam). A power form equation was obtained for the relation between the species mean leaf‐fall rate per tree (L/N or lm) and bam. RGRbam was correlated with leaf‐fall rate per unit basal area (L/BA) rather than with bam. This suggested that RGRbam is associated less with mean tree size (bam) and dominance as total basal area (BA), and more with annual leaf production per unit basal area, provided that L is equal to the annual leaf production per species. Rhus succedanea, the most dominant species in the forest plot, was typical in that it showed lower values of RGRbam and L/BA than other tree species. This would suggest a decline of R. succedanea in a secondary forest.

Growth-Competition Relationships in Young Hardwood Stands on Two Contrasting Sites in Southwestern Wisconsin

Abstract Crown-based competition measures were used to assess the relationships between growth and competition for trees in young mixed-hardwood stands on two ecosystems with contrasting site conditions. The two southwestern Wisconsin ecosystems compared were gently sloping summits with deep loessal soils and steeply sloping southwesterly backslopes with loam soils. Individual trees were sampled from variable-radius plots located in 15 stands of 4 to 42 years old. The two best predictors of height growth are the height of a tree relative to the average height of dominants and codominants, and the cross-sectional area of the exposed portion of the crown at its widest point. The data confirmed theoretical relationships between growth and light intensity for species of differing shade tolerance. However, growth rates as a function of relative height did not approach an asymptote for any species, while growth response to increasing exposed crown area was asymptotic for the tolerant species. Species' relationships differed between the two ecosystems, with maximum height growth rates being lower on the drier site. Acer saccharum was the most efficient species (highest basal area growth rate) at the higher values of exposed crown area, but larger total crown size for sugar maple was a contributing factor in such cases. For. Sci. 36(4):1032-1049.

Sap Sweetness Consistency vs. Growth Rates in Young Sugar Maples

Abstract Mature sugar maples have been shown in a previous study to be consistent for sap sweetness when ranked against other trees in a population for many years. This study examined sap sweetness in young sugar maples in relation to basal area growth rates. A definite trend toward consistency for sap sweetness was found in young trees although there was greater variability than in mature trees. Reasons for this variability are postulated to be the continuing competitive growth of the younger trees and mortality due to natural causes and/or management. However, the trend toward consistency for sweetness warrants sap testing as a criterion in selecting potential crop trees for sap production. Annual correlations between sap sweetness and growth rates varied with no clear trend. North. J. Appl. For. 7(1):5-9, March 1990.