Quantifying stem growth loss at the tree-level in a Pinus radiata plantation to repeated attack by the aphid, Essigella californica

2011 ◽  
Vol 261 (1) ◽  
pp. 120-127 ◽  
Author(s):  
Alieta Eyles ◽  
Andrew P. Robinson ◽  
David Smith ◽  
Angus Carnegie ◽  
Ian Smith ◽  
...  
2003 ◽  
Vol 33 (11) ◽  
pp. 2067-2073 ◽  
Author(s):  
W A Neilsen ◽  
E A Pinkard

Pruning of plantation trees is completed to produce knot-free timber and veneer logs, thus increasing the value of the plantation. A long-term study (11 years) was established to investigate the effects of selective pruning on radiata pine (Pinus radiata D. Don) stem growth. The 175 stems selected for the experiment had been pruned to 2.4 m at 6 years of age. At ages 8 and 10, the trees were pruned to 45%, 60%, or 75% of tree height and growth was compared with a control (first lift pruned only). Pruning to 45% of tree height had no effect on growth to age 13 years. Responses to the other treatments were apparent soon after pruning and continued until measurements ceased at 17 years of age. Pruning to 60% or 75% of tree height at second lift reduced diameter increment, and increment decreased as pruning severity increased. There was a further separation of the growth curves following third-lift pruning to 60% or 75% of tree height. The results suggested that maintaining a live crown ratio of 55% would minimize effects of pruning on diameter growth. The effect of severe pruning on diameter increment was greater for subdominant trees than for dominant stems. Pruning had less effect on height than diameter increment, but all treatments involving pruning to 75% of height at third lift resulted in trees that were approximately 10% shorter than unpruned trees at 13 years of age. More severe second-lift pruning resulted in smaller diameter over stubs at the time of third-lift pruning. Second-lift pruning to 60% of total height produced acceptable diameter over stubs. Implications for management are discussed.


1992 ◽  
Vol 52 (1-4) ◽  
pp. 117-137 ◽  
Author(s):  
M.L. Benson ◽  
B.J. Myers ◽  
R.J. Raison

2008 ◽  
Vol 61 ◽  
pp. 390-390
Author(s):  
A.J.M. Hopkins ◽  
M.A. Dick ◽  
I.G. Simpson

In southern New Zealand Neonectria fuckeliana is associated with a stem flute canker of Pinus radiata which can result in severe stem malformation and growth loss This research consisting of three distinct experiments aimed to determine pathogen survival in processed and unprocessed wood and woody debris In the first experiment the survival of the pathogen in living trees was examined by sampling trees infected with N fuckeliana in 6 different years In the second experiment the survival of the pathogen in woody debris was examined using 36 infected logs in a range of sizeclasses The logs were left on the forest floor in shaded and unshaded conditions and sampled for N fuckeliana after 4 and 9 months The third experiment examined the survival of the pathogen in processed wood Boards cut from infected trees were tested in six standard timber drying treatments Boards were sampled before and after drying to determine the presence of living N fuckeliana Neonectria fuckeliana was successfully isolated from trees at all infection times tested The fungus was also successfully isolated from 81 of logs after 9 months on the forest floor There was no significant difference between shaded and unshaded treatments Neonectria fuckeliana was not found in any boards following kilndrying but was successfully isolated from 69 of infected boards subjected to the two standard airdrying treatments for 9 weeks


2005 ◽  
Vol 35 (5) ◽  
pp. 1156-1172 ◽  
Author(s):  
Roderick D Ball ◽  
Mike S McConchie ◽  
Dave J Cown

Wood anatomical characteristics of twenty-nine 6-year-old Pinus radiata D. Don trees, selected to represent the extremes of intraring checking, were assessed with SilviScan. Derived ring-level summary variables were calculated from the SilviScan pith-to-bark wood property traces, based on ring means, standard deviations, and quantiles. Incidence of checking was assessed on discs that had been oven dried using a standardized method, and evidence for associations between wood characteristics and checking was evaluated at the tree and ring level using Bayesian statistical methods. Bayes factors of 39.1, 14.9, and 7.8 were obtained at the tree level, representing moderate to good evidence for associations between ring medians of wood density, tracheid radial diameter, and cell wall thickness, respectively. Increasing wood density, decreasing tracheid radial diameter, and increasing cell wall thickness were associated with reduced incidence of checking. These are parameters expected a priori to contribute to tracheid cells' resistance to collapse under drying stresses. A generalized linear model with radial diameter and cell wall thickness as independent variables had a concordance of 83% for predicting the checking status of trees.


1999 ◽  
Vol 5 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Stephen M. Thomas ◽  
David Whitehead ◽  
JefF. B. Reid ◽  
Freeman J. Cook ◽  
JohN. A. Adams ◽  
...  

Author(s):  
Juan Rodríguez-Gamir ◽  
Jianming Xue ◽  
Dean F Meason ◽  
Michael Clearwater ◽  
Peter W Clinton ◽  
...  

Abstract Stem growth reflects genetic and phenotypic differences within a tree species. The plant hydraulic system regulates the carbon economy, and therefore variations in growth and wood density. A whole-organism perspective, by partitioning the hydraulic system, is crucial for understanding the physical and physiological processes that co-ordinately mediate plant growth. The aim of this study was to determine whether the relationships and trade-offs between (1) hydraulic traits and their relative contribution to whole-plant hydraulic system, (2) plant water transport, (3) CO2 assimilation, (4) plant growth and (5) wood density are revealed at inter-clonal level within a variable population of ten Pinus radiata (D. Don) clones for these characters. We demonstrated strong coordination between several plant organs regarding their hydraulic efficiency. Hydraulic efficiency, gas exchange and plant growth were intimately linked. Small reductions in stem wood density were related to large increase in sapwood hydraulic efficiency, and thus with plant growth. However, stem growth rate was negatively related with wood density. We discuss insights explaining the relationships and trade-offs of plant traits examined in this study, which provide better understanding of the existing coordination, likely genetic-dependent, between biophysical structure of wood, plant growth, hydraulic partitioning and physiological plant functions in P. radiata.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xinsheng Liu ◽  
Emanuele Ziaco ◽  
Franco Biondi

Water-use efficiency (WUE), weighing the balance between plant transpiration and growth, is a key characteristic of ecosystem functioning and a component of tree drought resistance. Seasonal dynamics of tree-level WUE and its connections with drought variability have not been previously explored in sky-island montane forests. We investigated whole-tree transpiration and stem growth of bristlecone (Pinus longaeva) and limber pine (Pinus flexilis) within a high-elevation stand in central-eastern Nevada, United States, using sub-hourly measurements over 5 years (2013–2017). A moderate drought was generally observed early in the growing season, whereas interannual variability of summer rains determined drought levels between years, i.e., reducing drought stress in 2013–2014 while enhancing it in 2015–2017. Transpiration and basal area increment (BAI) of both pines were coupled throughout June–July, resulting in a high but relatively constant early season WUE. In contrast, both pines showed high interannual plasticity in late-season WUE, with a predominant role of stem growth in driving WUE. Overall, bristlecone pine was characterized by a lower WUE compared to limber pine. Dry or wet episodes in the late growing season overrode species differences. Our results suggested thresholds of vapor pressure deficit and soil moisture that would lead to opposite responses of WUE to late-season dry or wet conditions. These findings provide novel insights and clarify potential mechanisms modulating tree-level WUE in sky-island ecosystems of semi-arid regions, thereby helping land managers to design appropriate science-based strategies and reduce uncertainties associated with the impact of future climatic changes.


Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 639
Author(s):  
Shah Rukh ◽  
Werner Poschenrieder ◽  
Michael Heym ◽  
Hans Pretzsch

Frequency of drought years is expected to increase through climate warming. Mixed stands have often shown to be more productive than monospecific stands in terms of yield and of resistance against windthrows and bark beetle attacks. Mixture of beech and spruce is of particular interest. However, little is known about its growth reaction to drought. Therefore, we investigated the drought reaction of beech and spruce in mixed vs. monospecific stands along an ecological gradient. In particular, we sought evidence for mixture-related resilience on the individual tree level. Therefore, we quantified the response of tree ring width to drought. Moreover, we attempted to explain the relevance of individual tree response on the stand level by quantifying the stand level loss of volume growth after drought. At the individual tree level, beech was found to be more resilient and resistant in pure vs. mixed stands. Spruce, in contrast, was favored by mixture, and this was especially evident on drier sites. Along the gradient, growth losses at stand level increased in both mixed and pure stands in 2015, with growth gains on the drier sites observed in the same drought year, in accordance with the Stress Gradient Hypothesis. However, the stand level difference of growth loss between mixed and pure stands was not statistically significant. Mitigating mixture effects on the level of the individual tree thus did not become evident on the level of the whole stand.


Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Mary Anne S. Sayer ◽  
Michael C. Tyree ◽  
Eric A. Kuehler ◽  
John K. Jackson ◽  
Dylan N. Dillaway

We hypothesized that physiological and morphological responses to prescribed fire support the post-scorch foliage recovery and growth of young longleaf pine. Two studies conducted in central Louisiana identified three means of foliage regrowth after fire that included an increase in the gas exchange rate of surviving foliage for 3 to 4 months after fire. Saplings also exhibited crown developmental responses to repeated fire that reduced the risk of future crown scorch. Starch reserves were a source of carbon for post-scorch foliage regrowth when fire was applied in the early growing season. However, the annual dynamics of starch accumulation and mobilization restricted its effectiveness for foliage regrowth when fire was applied late in the growing season. As such, post-scorch foliage regrowth became increasingly dependent on photosynthesis as the growing season progressed. Additionally, the loss of foliage by fire late in the growing season interrupted annual starch dynamics and created a starch void between the time of late growing season fire and mid-summer of the next year. The occurrence of drought during both studies revealed barriers to foliage reestablishment and normal stem growth among large saplings. In study 1, spring water deficit at the time of May fire was associated with high crown scorch and poor foliage and stem growth among large saplings. We attribute this lag in stem growth to three factors: little surviving foliage mass, low fascicle gas exchange rates, and poor post-scorch foliage recovery. In study 2, May fire during a short window of favorable burning conditions in the tenth month of a 20-month drought also reduced stem growth among large saplings but this growth loss was not due to poor post-scorch foliage recovery. Application of this information to prescribed fire guidelines will benefit young longleaf pine responses to fire and advance efforts to restore longleaf pine ecosystems.


1999 ◽  
Vol 75 (1) ◽  
pp. 141-152 ◽  
Author(s):  
Thom A. Erdle ◽  
David A. MacLean

Quantitative assessment of forest pest impacts is an important element in design of forest and pest management programs. Such assessment requires forecasts of pest populations, definition of the nature and extent of damage inflicted on trees by those populations, and translation of the damage effects across scales, from the tree to the stand to the forest. Central to this process are stand development forecasts which embody tree-level impacts of damage and which provide input to forest-level models. We discuss the role of stand growth forecasting in this context and propose a method for calibrating stand growth models that can be used to incorporate the effects of pest damage on tree and stand development. This calibration methodology is demonstrated for spruce budworm (Choristoneura fumiferana Clem.) effects on spruce (Picea sp.) and balsam fir (Abies balsamea (L.) Mill.) stands using permanent sample plot data acquired in New Brunswick over the past 20 years. The results showed linear relationships between tree diameter growth loss and cumulative defoliation, and non-linear relationships between reduced survival and cumulative defoliation. Growth loss relationships were similar for the species considered, while reduced survival relationships varied between species and age classes. Using these relationships as input to the STAMAN stand growth model, forecasts were made and compared against empirical studies of stand development under defoliation during spruce budworm outbreaks. The results suggest that reasonable approximations of stand response to pest incidence can be generated with relatively simple models and data sets. Judicious use of stand growth forecasts generated by such methods can help serve the needs of forest and pest management strategy design. Key words: spruce budworm, defoliation, stand growth model, stand development, growth loss, mortality


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