Spatio-temporal effects of forest canopy on understory microclimate in a long-term experiment in Switzerland
Georg Von Arx, Matthias Dobbertin & Martine Rebetez
| Résumé |
Forest canopy generally moderates below-canopy air temperature and
relative humidity and thus creates a specific microclimate for tree
seedling growth. Climate change will alter the moderating capacity,
which may render the below-canopy conditions unsuitable for
recruitment of the hitherto dominant tree species. We assigned
long-term meteorological data (1997-2010) recorded inside and
outside of 14 different forest ecosystems in Switzerland to three
forest types (broadleaved, non-pine conifer, pine), two altitudinal
levels (low, high), the four seasons and general weather situations
(normal, hot/dry, cold/wet) to compare moderating capacity of each
of these classifiers. Our results confirmed a general moderating
effect of canopy on below-canopy microclimate with a decrease of
daily maximum air temperature of up to 5.1 degrees C (overall
average: 1.8 degrees C) and an increase of daily minimum relative
humidity of up to 12.4% (overall average: 5.1%) in the long-term
average, respectively. Broadleaved and non-pine conifer forests
moderated daytime microclimate about twice as much as pine forests,
while at nighttime considerably less cooling down and even negative
effects on levels of relative humidity compared to the open area
were recorded at the pine forest sites. Moderating capacity was
stronger at low altitude than at high altitude. It was strongest
during the growing season, particularly in summer, and depended in
a complex way on the general weather situation. Deviations from the
general seasonal and weather condition patterns most likely occurred
when soil moisture pools were depleted. Despite the moderating
capacity, below-canopy microclimate did not lag behind open area
microclimate. Based on our results we conclude that natural
recruitment in pine forests and high-altitude forests may respond
most sensitively to climate change. (c) 2012 Elsevier B.V. All
rights reserved. |
| Citation | von Arx, G., Dobbertin, M., & Rebetez, M. (2012). Spatio-temporal effects of forest canopy on understory microclimate in a long-term experiment in Switzerland. Agricultural and Forest Meteorology, 166, 144-155. |
| Type | Article de périodique (Anglais) |
| Date de publication | 2012 |
| Nom du périodique | Agricultural and Forest Meteorology |
| Volume | 166 |
| Pages | 144-155 |