Changes in height growth patterns in the upper tree-line forests of Tierra del Fuego in relation to climate change

Abstract

Changes in height growth patterns in the upper tree-line forests of Tierra del Fuego in relation to climate change SUMMARYNothofagus pumilio occupy the mountain slopes reaching to the upper altitudinal limit of the forests. This extremely stressful environment represents the optimum conditions to study changes in growth patterns due to climate variations. Our goal was to analyze recent changes in stem height growth in forests located in the upper altitudinal tree-line along Tierra del Fuego (Argentina), and establish possible linkages to changes observed in surface temperature during the last decades. Nine locations were sampled, and four plots were measured in each location. Forest structure was characterized, and stem analyses were performed to assess height growth patterns. ANOVAs and classification analyses were conducted using location and time as main variables. Tree-growth height increased with time, e.g. 1.0 cm.year -1 during 1870-1959, 2.7 cm year -1 during 1960-1979, and 5.0 cm year -1 during 1980-2010. These differences were significant between periods and locations, and can be related to its geographical situation. Increment in stem height growth seems to be related with the worldwide surface air temperature. A decline in stem height growth registered during the last two decades can also be related with the regional decrease in the mean air temperature. The analysis of stem height growth is a useful tool to evaluate the incidence of climate change over trees growing under extreme environmental conditions.

The influence of canopy-layer composition on understory plant diversity in southern temperate forests

“…At these high latitudes, tree growth and distribution is most sensitive to climatic conditions (Hertel et al 2008;Massaccesi et al 2008;Ivancich et al 2012), and therefore, a shift in plant communities forced by climate change would be more evident. In Southern Patagonia, the maximum temperature and annual precipitation are predicted to increase until the end of the twenty-first century, possibly leading to a higher net primary productivity ).…”

Flowering and seeding patterns in pure and mixed Nothofagus forests in Southern Patagonia

“…Native forests in Tierra del Fuego Island grow naturally under extreme environmental conditions, controlled by Atlantic Ocean, the influence of the Antarctic climate and the Andes Mountains, by generating strong climate gradients at regional levels (Kreps et al 2012). At these high latitudes, tree growth is most sensitive to climatic conditions (Hertel et al 2008;Massaccesi et al 2008;Ivancich et al 2012), and therefore, a shift in community composition forced by climate change would be more evident. This study will contribute to understanding of the possible roles of reproductive phenology for detecting shifts in forest communities between pure and mixed forests under natural dynamics and the current climate regime.…”

Long-term monitoring of thinning for silvopastoral purposes in Nothofagus antarctica forests of Tierra del Fuego, Argentina

“…increasing crown cover), which can be related to the natural development of the stand (e.g. Ivancich et al, 2011Ivancich et al, , 2014 or climate change effects (Kreps et al, 2012) which occurring in the last decades in Tierra del Fuego (Ivancich et al, 2012). In summary, intensive thinning in Nothofagus antarctica secondary forests increased individual tree growth rates and doubling the radiation levels at the understory level, achieving the main objectives of the silvopastoral management.…”