Statistics for Spatial Data.

https://hal.archives-ouvertes.fr/hal-00457602/document

A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests

Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

/pdf/climate-change-2007-the-physical-science-basis-1x93ttz9jt.pdf

Climate Change 2007: The Physical Science Basis.

Summary Severe droughts have been associated with regional-scale forest mortality worldwide. Climate change is expected to exacerbate regional mortality events; however, pre- diction remains difficult because the physiological mechanisms underlying drought survival and mortality are poorly understood. We developed a hydraulically based theory considering carbon balance and insect resistance that allowed development and examination of hypotheses regarding survival and mortality. Multiple mechanisms may cause mortality during drought. A common mechanism for plants with isohydric

/pdf/mechanisms-of-plant-survival-and-mortality-during-drought-5rza45sn4g.pdf

Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought?

On 13 October 1908, Fritz Haber filed his patent on the "synthesis of ammonia from its elements" for which he was later awarded the 1918 Nobel Prize in Chemistry. A hundred years on we live in a world transformed by and highly dependent upon Haber–Bosch nitrogen.

How a century of ammonia synthesis changed the world

During the 20th century, high mortality rates of Scots pine (Pinus silvestris L.) have been observed over large areas in the Rhone valley (Valais, Switzerland) and in other dry valleys of the European Alps. In this study, we evaluated drought as a possible inciting factor of Scots pine decline in the Valais. Averaged tree-ring widths, standardized tree-ring series, and estimated annual mortality risks were related to a drought index. Correlations between drought indices and standardized tree-ring series from 11 sites showed a moderate association. Several drought years and drought periods could be detected since 1864 that coincided with decreased growth. Although single, extreme drought years had generally a short-term, reversible effect on tree growth, multi-year drought initiated prolonged growth decreases that increased a tree’s long-term risk of death. Tree death occurred generally several years or even decades after the drought. In conclusion, drought has a limiting effect on tree growth and acts as a bottleneck event in triggering Scots pine decline in the Valais.

/pdf/drought-as-an-inciting-mortality-factor-in-scots-pine-stands-2dl5vy5hki.pdf

Drought as an Inciting Mortality Factor in Scots Pine Stands of the Valais, Switzerland

The intensive monitoring plots (Level II) of ICP Forests serve to examine the effects of air pollution and other stress factors on forest condition, including tree vitality. However, tree vitality cannot be measured directly. Indicators, such as tree growth or crown transparency, may instead be used.

/pdf/tree-growth-as-indicator-of-tree-vitality-and-of-tree-1jm6n4c0qs.pdf

Matthias Dobbertin

Papers

Drought as an Inciting Mortality Factor in Scots Pine Stands of the Valais, Switzerland

Tree growth as indicator of tree vitality and of tree reaction to environmental stress: a review

Evaluation of competition indices in individual tree growth models

The impact of nitrogen deposition on carbon sequestration by European forests and heathlands

A comparison of distance-dependent competition measures for height and basal area growth of individual conifer trees.