This study attempted to detect the impact of ozone on adult trees of Norway spruce ( Picea abies [L.] Karst.) and European beech ( Fagus sylvatica L.) in an experimental mixed stand in Southern Bavaria, Germany. The aim was to examine whether there is a decrease in growth when trees are exposed to higher than atmospheric concentrations of ozone. This exposure was put into effect using a free-ai...

What is a tree? The popular concept of a tree, which encompasses everything from treeferns and Joshua trees to coconut palms and oaks, confounds any simple botanical definition. Nevertheless, almost all ‘trees’ have one (rarely a few) above ground, perennial vegetative shoots, of a size requiring significant nonhydrostatic structural support. In a typical seed plant tree, this structural tissue...

North-Central China is a region in which the air temperature has clearly increased for several decades. Picea meyeri and Larix principis-rupprechtii are the most dominant co-occurring tree species within the cold coniferous forest belt ranging vertically from 1800 m to 2800 m a.s.l. in this region. Based on a tree-ring analysis of 292 increment cores sampled from 146 trees at different elevatio...

All individuals of Cedrela lilloi (a valuable timber species of Meliaceae) > 4 cm DBH were sampled in three rectangular plots (c. 15 000 m each) in northwestern Argentina subtropical montane forests between 850 and 1350 m. Regeneration dynamics of C. lilloi was characterized by testing two hypotheses: (i) C. lilloi has a gap-phase regeneration mode, which implies a negative exponential size/age...

BACKGROUND Coppicing was one of the most important forest management systems in Europe documented in prehistory as well as in the Middle Ages. However, coppicing was gradually abandoned by the mid-20(th) century, which has altered the ecosystem structure, diversity and function of coppice woods. METHODOLOGY/PRINCIPAL FINDINGS Our aim was to disentangle factors shaping the historical growth dy...

There is controversy regarding the limiting climatic factor for tree radial growth at the alpine treeline on the northeastern Tibetan Plateau. In this study, we collected 594 increment cores from 331 trees, grouped within four altitude belts spanning the range 3550 to 4020 m.a.s.l. on a single hillside. We have developed four equivalent ring-width chronologies and shown that there are no signif...

Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two...

Questions: Do large, old Sequoiadondron giganteum trees respond to the creation of adjacent canopy gaps? Do other co-occurring tree species and younger S. giganteum adjacent to gaps also respond? What are the likely factors affecting growth responses? Location: Mixed-conifer forests of the southern Sierra Nevada, California, USA. Methods: We measured the growth response of large, old S. gigante...

A linkage is a collection of line segments, called bars, possibly joined at their ends, called joints. We consider flattening a tree-like linkage, that is, a continuous motion of their bars from an initial configuration to a final configuration looking like a“straight line segment,” preserving the length of each bar and not crossing any two bars. In this paper, we introduce a new class of linka...