Leaf area and growth of Chilean radiata pine plantations after thinning across a water stress gradient

Abstract

Background: Pinus radiata D.Don has been established in a wide range of soils and climatic conditions, showing high variability in both leaf area and volume productivity. Previous research has shown that plantation yield is affected by water availability, but the majority of this work has been done in unthinned stands and provided little insight on the effect of water availability on the productivity of thinned plantations. In order to improve forest productivity for plantations under a climate change scenario, we must understand the effect of plantation management, including thinning on the relationships among available water, leaf area index, and productivity. The aim of this work is to evaluate the effect of site water availability on the leaf area production and consequent volume growth in thinned radiata pine plantations over a water availability gradient. Methods: The effect of site available water on leaf area production and consequent volume growth in thinned Pinus radiata plantations over a water availability gradient across five sites in central and southern-central Chile was determined. Results: Regression analysis revealed water deficit to be related to both leaf area index and volume growth accounting for 77 and 78% of the variation respectively. Eighty-one percent of the variation in volume growth was explained by the leaf area index. Results showed a growth efficiency of 5 m 3 ha −1 per unit of leaf area index. Conclusions: Strong linear positive relationships between site water availability, leaf area, and stand growth after thinning found in this research suggest that water is the key factor controlling current productivity of radiata pine plantations across sites. A simple and robust water index that is well correlated with leaf area and stand annual volume growth allows for the construction of a simple predictive model that may support management decisions for radiata pine plantations.

Within-Site Variation in Seedling Survival in Norway Spruce Plantations

“…Increases in variation in annual climatic parameters, due to future climate change, may increase the value of robust predictions of drought-related mortality in scarification method decisions. Examples of such ecophysiological responses to interactive climate, site and management variations might not be common yet in northern Europe, but there are numerous examples from other regions with plantation forestry [20,21]. There were almost equal distributions of containerized and bare-rooted seedlings, and no difference in their survival rate was detected in this study, in accordance with findings of several experimental studies that both seedling types have pros and cons [22,23].…”

Capturing ecological processes in dynamic forest models: why there is no silver bullet to cope with complexity

“…Yet, our results suggest that the growth of trees that are constrained by one environmental factor only (e.g., suppressed trees growing under low‐light conditions in an otherwise favorable habitat) may be overestimated, which results in an underestimation of stress‐induced mortality. Thus, further investigations are needed regarding the growth‐reducing factors and their combination into one single annual scalar and the variability of dbh increments between individual trees, years, or sites, which is known to be substantial (Bleicher 2013, Weber et al 2013), for example, by exploiting inventory and tree‐ring data along environmental gradients (Weber et al 2013, Ojeda et al 2018).…”

Trees Talk Tremor—Wood Anatomy and Content Reveal Contrasting Tree‐Growth Responses to Earthquakes

“…(2012) and Ojeda et al. (2018) reported highly variable, rainfall‐driven, growth in pine plantations within or close to the rupture zone of the Maule earthquake. However, we can exclude that rainfall raised the soil moisture on the valley floor, because conditions for several days prior to the earthquake were dry.…”

“…Given mostly SSE‐facing hillslopes and indistinguishable tree height distributions (Huber et al., 2010), we exclude higher irradiance along the valley bottom as a reason for this site‐specific difference (Table ). Instead, growth of Pinus radiata in Mediterranean areas such as south‐central Chile is generally water‐limited (Ojeda et al., 2018), thus following a temporal pattern determined by water supply in the rainy season. We thus argue that tree growth (and photosynthesis) here is primarily controlled by water supply, given the strong correlations between and wood anatomic proxies with topographic proxies for soil‐water availability.…”

“…While enlarging the tracheids, water can only enter the expanding cell if the apoplastic water potential is higher than the symplastic water potential (Carvalho et al, 2015). Álvarez et al (2012) and Ojeda et al (2018) reported highly variable, rainfall-driven, growth in pine plantations within or close to the rupture zone of the Maule earthquake. However, we can exclude that rainfall raised the soil moisture on the valley floor, because conditions for several days prior to the earthquake were dry.…”