scholarly journals Estimation and Uncertainty of the Mixing Effects on Scots Pine—European Beech Productivity from National Forest Inventories Data

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 518 ◽  
Author(s):  
Sonia Condés ◽  
Hubert Sterba ◽  
Ana Aguirre ◽  
Kamil Bielak ◽  
Andrés Bravo-Oviedo ◽  
...  
Keyword(s):  
Scots Pine ◽  
Large Scale ◽  
Basal Area ◽  
European Beech ◽  
Site Factors ◽  
Mixed Stands ◽  
Mixing Effects ◽  
Basal Area Growth ◽  
Area Growth ◽  
Regional Forest

An increasing amount of research is focusing on comparing productivity in monospecific versus mixed stands, although it is difficult to reach a general consensus as mixing effects differ both in sign (over-yielding or under-yielding) and magnitude depending on species composition as well as on site and stand conditions. While long-term experimental plots provide the best option for disentangling the mixing effects, these datasets are not available for all the existing mixtures nor do they cover large gradients of site factors. The objective of this study was to evaluate the effects and uncertainties of tree species mixing on the productivity of Scots pine–European beech stands along the gradient of site conditions in Europe, using models developed from National and Regional Forest Inventory data. We found a positive effect of pine on beech basal area growth, which was slightly greater for the more humid sites. In contrast, beech negatively affected pine basal area growth, although the effects switched to positive in the more humid sites. However, the uncertainty analysis revealed that the effect on pine at mid- and more humid sites was not-significant. Our results agree with studies developed from a European transect of temporal triplets in the same pine–beech mixtures, confirming the suitability of these datasets and methodology for evaluating mixing effects at large scale.

scholarly journals Species Mixing Effects on Height–Diameter and Basal Area Increment Models for Scots Pine and Maritime Pine

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 249 ◽  
Author(s):  
José Riofrío ◽  
Miren del Río ◽  
Douglas Maguire ◽  
Felipe Bravo
Keyword(s):  
Scots Pine ◽  
Tree Growth ◽  
Growth Models ◽  
Basal Area ◽  
Maritime Pine ◽  
Basal Area Increment ◽  
Mixing Effects ◽  
Basal Area Growth ◽  
Area Growth ◽  
Species Mixtures

Models that incorporate known species-mixing effects on tree growth are essential tools to properly design silvicultural guidelines for mixed-species stands. Here, we developed generalized height–diameter (h-d) and basal area growth models for mixed stands of two main forest species in Spain: Scots pine (Pinus sylvestris L.) and Maritime pine (Pinus pinaster Ait.). Mixed-effects models were fitted from plot measurement and tree rings data from 726 Scots pine and 693 Maritime pine trees from mixed and pure stands in the Northern Iberian Range in Spain, with the primary objective of representing interactions between the species where they are interspersed in mixtures of varying proportions. An independent dataset was used to test the performance of the h-d models against models previously fitted for monospecific stands of both species. Basal area increment models were evaluated using a 10-fold block cross-validation procedure. We found that species mixing had contrasting effects on the species in both models. In h-d models, the species-mixing proportion determined the effect of species interactions. Basal area growth models showed that interspecific competition was influential only for Maritime pine; however, these effects differed depending on the mode of competition. For Scots pine, tree growth was not restricted by interspecies competition. The combination of mixed-effect models and the inclusion of parameters expressing species-mixing enhanced estimates of tree height and basal area growth compared with the available models previously developed for pure stands. Although the species-mixing effects were successfully represented in the fitted models, additional model components for accurately simulating the stand dynamics of mixtures with Scots pine and Maritime pine and other species mixtures require similar model refinements. Upon the completion of analyses required for these model refinements, the degree of improvement in simulating growth in species mixtures, including the effects of different management options, can be evaluated.

Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon

2002 ◽  
Vol 32 (7) ◽  
pp. 1232-1243 ◽  
Author(s):  
Nathan J Poage ◽  
John C Tappeiner, II
Keyword(s):  
Large Diameter ◽  
Basal Area ◽  
Douglas Fir ◽  
Slope Aspect ◽  
Site Factors ◽  
Old Growth ◽  
Site Class ◽  
Basal Area Growth ◽  
Area Growth ◽  
Age Range

Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100–300 years. The diameters of the trees at ages 100–300 years (D100–D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments (PAIBA) of all trees increased for the first 30–40 years and then plateaued, remaining relatively high and constant from age 50 to 300 years. Average PAIBA of the largest trees at ages 100–300 years were significantly greater by age 20 years than were those of smaller trees at ages 100–300 years. The site factors province, site class, slope, aspect, elevation, and establishment year accounted for little of the variation observed in basal area growth at age 50 years and D100–D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations.

Individual-tree basal area growth models for jack pine and black spruce in northern Ontario

2004 ◽  
Vol 80 (3) ◽  
pp. 366-374 ◽  
Author(s):  
Lianjun Zhang ◽  
Changhui Peng ◽  
Qinglai Dang
Keyword(s):  
Tree Growth ◽  
Black Spruce ◽  
Basal Area ◽  
Jack Pine ◽  
Mixed Stands ◽  
Northern Ontario ◽  
Individual Tree ◽  
Basal Area Growth ◽  
Wide Range ◽  
Area Growth

Individual-tree models of five-year basal area growth were developed for jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP) in northern Ontario. Tree growth data were collected from long-term permanent plots of pure and mixed stands of the two species. The models were fitted using mixed model methods due to correlated remeasurements of tree growth over time. Since the data covered a wide range of stand ages, stand conditions and tree sizes, serious heterogeneous variances existed in the data. Therefore, the coefficients of the final models were obtained using weighted regression techniques. The models for the two species were evaluated across 4-cm diameter classes using independent data. The results indicated (1) the models of jack pine and black spruce produced similar prediction errors and biases for intermediate-sized trees (12–28 cm in tree diameter), (2) both models yielded relatively large errors and biases for larger trees (> 28 cm) than those for smaller trees, and (3) the jack pine model produced much larger errors and biases for small-sized trees (< 12 cm) than did the black spruce model. Key words: mixed models, repeated measures, model validation

Less is more: Effects of competition reduction and facilitation on intra-annual (basal area) growth of mature European beech

Trees ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 17-36 ◽  
Author(s):  
Jérôme Metz ◽  
Peter Annighöfer ◽  
Katharina Westekemper ◽  
Peter Schall ◽  
Ernst-Detlef Schulze ◽  
...  
Keyword(s):  
Basal Area ◽  
European Beech ◽  
Less Is More ◽  
Basal Area Growth ◽  
Area Growth

Field Notes: Predicted Vs. Actual Basal Area Growth in West Virginia

1988 ◽  
Vol 5 (3) ◽  
pp. 221-222
Author(s):  
Arlyn W. Perkey ◽  
Kenneth L. Carvell
Keyword(s):  
West Virginia ◽  
Basal Area ◽  
Basal Area Growth ◽  
Area Growth ◽  
Field Notes

A New Index Representing Individual Tree Competitive Status

1973 ◽  
Vol 3 (4) ◽  
pp. 495-500 ◽  
Author(s):  
James A. Moore ◽  
Carl A. Budelsky ◽  
Richard C. Schlesinger
Keyword(s):  
Spatial Distribution ◽  
Strong Correlation ◽  
Basal Area ◽  
Tree Size ◽  
Competition Index ◽  
Individual Tree ◽  
Silvicultural Practices ◽  
Basal Area Growth ◽  
Hardwood Species ◽  
Area Growth

A new competition index, modified Area Potentially Available (APA), was tested in a complex unevenaged stand composed of 19 different hardwood species. APA considers tree size, spatial distribution, and distance relationships in quantifying intertree competition and exhibits a strong correlation with individual tree basal area growth. The most important characteristic of APA is its potential for evaluating silvicultural practices.

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