scholarly journals The Effects of Initial Spacing and Rectangularity on the Early Growth of Hybrid Poplar

2008 ◽  
Vol 23 (4) ◽  
pp. 189-196 ◽  
Author(s):  
Wayne D. Johnstone
Keyword(s):  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Early Growth ◽  
Row Spacing ◽  
Individual Tree ◽  
Tree Diameter ◽  
Initial Spacing ◽  
The Individual ◽  
Plantation Spacing

Abstract Hybrid poplar (Populus trichocarpa Torr. and Gray × Populus deltoides Marsh.) plantations, at two locations in southern British Columbia, were examined 9 years after planting, to determine the effects of plantation spacing on individual-tree and per-hectare growth and development. At both locations, spacing had a direct, significant effect on virtually all of the individual-tree characteristics examined. For a given amount of growing space per tree, rectangularity (within-row/between-row spacing ratios) had no significant effect on individual-tree diameter, height, or total bole volume. Virtually all of the per-hectare characteristics examined were not significantly affected by spacing at either location.

Bt-Cry3Aa transgene expression reduces insect damage and improves growth in field-grown hybrid poplar

2014 ◽  
Vol 44 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Amy L. Klocko ◽  
Richard Meilan ◽  
Rosalind R. James ◽  
Venkatesh Viswanath ◽  
Cathleen Ma ◽  
...  
Keyword(s):  
Large Scale ◽  
Populus Deltoides ◽  
Integrated Management ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Volume Growth ◽  
Field Trials ◽  
Leaf Beetle ◽  
Insect Damage ◽  
Beetle Damage

The stability and value of transgenic pest resistance for promoting tree growth are poorly understood. These data are essential for determining if such trees could be beneficial to commercial growers in the face of substantial regulatory and marketing costs. We investigated growth and insect resistance in hybrid poplar expressing the cry3Aa transgene in two field trials. An initial screening of 502 trees comprising 51 transgenic gene insertion events in four clonal backgrounds (Populus trichocarpa × Populus deltoides, clones 24-305, 50-197, and 198-434; and P. deltoides × Populus nigra, clone OP-367) resulted in transgenic trees with greatly reduced insect damage. A large-scale study of 402 trees from nine insertion events in clone OP-367, conducted over two growing seasons, demonstrated reduced tree damage and significantly increased volume growth (mean 14%). Quantification of Cry3Aa protein indicated high levels of expression, which continued after 14 years of annual or biannual coppice in a clone bank. With integrated management, the cry3Aa gene appears to be a highly effective tool for protecting against leaf beetle damage and improving yields from poplar plantations.

scholarly journals Management strategies of Eremanthus erythropappus (DC.) MacLeish under different initial spacing

2016 ◽  
Vol 40 (3) ◽  
pp. 298-304 ◽  
Author(s):  
José Roberto Soares Scolforo ◽  
Thiza Falqueto Altoe ◽  
Henrique Ferraco Scolforo ◽  
Jose Marcio de Mello ◽  
Charles Plinio Castro e Silva ◽  
...  
Keyword(s):  
Management Strategies ◽  
Tree Model ◽  
Individual Tree ◽  
Crown Area ◽  
High Durability ◽  
Spacing Variation ◽  
Generating Tree ◽  
Initial Spacing ◽  
Individual Tree Model ◽  
The Individual

ABSTRACT Eremanthus erythropappus, commonly known as candeia, is an income-generating tree native to Brazil. This is due to the high durability of its wood and its essential oil containing the active component alpha bisabolol. Despite this economic potential, until the early 2000's no studies existed to explore the sustainable management in areas in which the species naturally occurs or for establishing commercial plantations. This study proposes new management strategies based on an individual tree model, and evaluates the growth behavior of candeia trees planted in different spacing. The experiment was installed in March 2002, in Carrancas municipality, Minas Gerais state, Brazil. The experimental area was divided into 4 blocks with 4 different spacings as treatments. The individual model used to propose the best management system uses development of crown area as a function of DBH. The results showed that candeia trees were sensitive to initial spacing variation. With increased initial spacing, candeia trees reached competition later, as demonstrated by crown area development. Thus, candeia trees planted at a wider spacing maintain a desirable growth rate without need for thinning for a longer time, compared to trees planted at narrower spacing. The fitted individual tree model presented in this study showed consistent results and flexibility, providing alternatives for different management strategies. The best growth response was obtained for planting densities greater than 3.75 m² per tree, which corresponds to a spacing of 1.5 x 2.5 m.

scholarly journals Defining hybrid poplar (Populus deltoides × Populus trichocarpa) tolerance to ozone: identifying key parameters

2009 ◽  
Vol 32 (1) ◽  
pp. 31-45 ◽  
Author(s):  
A. RYAN ◽  
C. COJOCARIU ◽  
M. POSSELL ◽  
W. J. DAVIES ◽  
C. N. HEWITT
Keyword(s):  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar

scholarly journals Individual Tree Diameter Growth Models of Larch–Spruce–Fir Mixed Forests Based on Machine Learning Algorithms

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 187 ◽  
Author(s):  
Qiangxin Ou ◽  
Xiangdong Lei ◽  
Chenchen Shen
Keyword(s):  
Machine Learning ◽  
Tree Growth ◽  
Growth Models ◽  
Tree Size ◽  
Diameter Growth ◽  
Individual Tree ◽  
Mixed Forests ◽  
Tree Diameter ◽  
Individual Tree Growth ◽  
The Individual

Individual tree growth models are flexible and commonly used to represent growth dynamics for heterogeneous and structurally complex uneven-aged stands. Besides traditional statistical models, the rapid development of nonparametric and nonlinear machine learning methods, such as random forest (RF), boosted regression tree (BRT), cubist (Cubist) and multivariate adaptive regression splines (MARS), provides a new way for predicting individual tree growth. However, the application of these approaches to individual tree growth modelling is still limited and short of a comparison of their performance. The objectives of this study were to compare and evaluate the performance of the RF, BRT, Cubist and MARS models for modelling the individual tree diameter growth based on tree size, competition, site condition and climate factors for larch–spruce–fir mixed forests in northeast China. Totally, 16,619 observations from long-term sample plots were used. Based on tenfold cross-validation, we found that the RF, BRT and Cubist models had a distinct advantage over the MARS model in predicting individual tree diameter growth. The Cubist model ranked the highest in terms of model performance (RMSEcv [0.1351 cm], MAEcv [0.0972 cm] and R2cv [0.5734]), followed by BRT and RF models, whereas the MARS ranked the lowest (RMSEcv [0.1462 cm], MAEcv [0.1086 cm] and R2cv [0.4993]). Relative importance of predictors determined from the RF and BRT models demonstrated that the competition and tree size were the main drivers to diameter growth, and climate had limited capacity in explaining the variation in tree diameter growth at local scale. In general, the RF, BRT and Cubist models are effective and powerful modelling methods for predicting the individual tree diameter growth.

Phenotypic variation in growth and biomass distribution for two advanced-generation pedigrees of hybrid poplar

2005 ◽  
Vol 35 (8) ◽  
pp. 1779-1789 ◽  
Author(s):  
Stan D Wullschleger ◽  
T M Yin ◽  
S P DiFazio ◽  
T J Tschaplinski ◽  
L E Gunter ◽  
...  
Keyword(s):  
Genetic Control ◽  
Phenotypic Variation ◽  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Biological Research ◽  
Total Biomass ◽  
Biomass Distribution ◽  
Coarse Roots ◽  
Fractional Distribution

To assess the genetic control of biomass distribution in trees, phenotypic variation in the distribution of dry mass to stems, branches, leaves, coarse roots, and fine roots was examined in two hybrid poplar (Populus trichocarpa Torr. & A. Gray (T) × Populus deltoides Bartr. ex Marsh. (D)) families grown under field conditions. Family 331 was an inbred F2 (TD × TD) pedigree, whereas family 13 was an outbred backcross BC1 (TD × D) pedigree. Fractional distribution of total whole-tree biomass to shoots and roots during their establishment year averaged (±SD) 0.62 ± 0.09 and 0.38 ± 0.09, respectively, across 247 genotypes in family 331, and 0.57 ± 0.06 and 0.43 ± 0.06, respectively, across 160 genotypes in family 13. In contrast, fractional distribution of total biomass in 2-year-old trees was 0.79 ± 0.04 to shoots and 0.21 ± 0.04 to roots. Allometric analysis indicated that as trees increased in age, biomass was preferentially distributed to stems and branches, whereas distribution to roots declined. Quantitative trait loci (QTL) analysis for family 13 indicated 31 QTL (likelihood of odds >2.5) for traits measured. The percent phenotypic variation explained by any single QTL ranged from 7.5% to 18.3% and averaged 11.2% across all QTL. These results show that aboveground and belowground patterns of biomass distribution are under genetic control. This finding has wide-ranging implications for carbon sequestration, phytoremediation, and basic biological research in trees.

scholarly journals The CP4 transgene provides high levels of tolerance to Roundup® herbicide in field-grown hybrid poplars

2002 ◽  
Vol 32 (6) ◽  
pp. 967-976 ◽  
Author(s):  
R Meilan ◽  
K -H Han ◽  
C Ma ◽  
S P DiFazio ◽  
J A Eaton ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Populus Deltoides ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Field Studies ◽  
Glyphosate Tolerance ◽  
Hybrid Poplars ◽  
Transgenic Lines ◽  
Identical Number ◽  
Better Than

We tested two genes together in hybrid poplars (genus Populus), CP4 and GOX, for imparting tolerance to glyphosate (the active ingredient in Roundup® herbicide). Using Agrobacterium-based transformation, 80 independent transgenic lines (i.e., products of asexual gene transfer) were produced in a variety of hybrid poplar clones (40 lines in Populus trichocarpa Torr. & Gray × Populus deltoides Bartr., 35 lines in Populus tremula L. × Populus alba L., and five lines in P. tremula × Populus tremuloides Michx.). We evaluated glyphosate tolerance over 2 years in field studies conducted in eastern and western Oregon. Ten percent of our transgenic lines showed no foliar damage or reduced growth after being sprayed with Roundup® at concentrations above normal commercial rates. Lack of damage was associated with expression of the CP4 gene but not of the GOX gene. It was suspected that GOX caused undesirable side effects, so we produced 12 lines into which only the CP4 gene was inserted. The performance of these newly regenerated lines was compared with an identical number of lines, produced in the same genotype, that had previously been engineered to contain both CP4 and GOX. Growth of the lines transformed with just CP4 was significantly better than those containing both genes and exhibited less damage in response to glyphosate treatment. This is the first report of transgenic poplars exhibiting high levels of glyphosate tolerance when grown under field conditions. With a modest transformation effort, it is possible to produce lines with commercially useful levels of glyphosate tolerance and little apparent collateral genetic damage.

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