Douglas fir is a widely introduced species in Europe and has often been introduced as a promising alternative to more drought-sensitive species. However, recent field observations show an increased sensitivity of this species which compromises its ability to cope with drought.<\/p>\n
A study carried out in southern Belgium examined the growth response of Douglas-fir to drought, taking into account a number of drought characteristics (period, intensity and occurrence), site conditions (water balance, water availability), and stand densities. A total of 360 trees aged between 48 and 67 years were monitored at 24 sites in Wallonia.<\/p>\n
The results of the study show that, on average, Douglas-fir growth declined during droughts, regardless of drought characteristics and site conditions. Trees always recovered, but not always with maximum resilience. Drought characteristics had a greater influence on drought response than site and stand characteristics. For example, negative impacts on growth were greatest during early droughts (vs. late droughts) and during more intense and consecutive droughts. Stand density had no significant effect.<\/p>\n
In conclusion, Douglas-fir is most likely to be fully resilient to drought when droughts are later, less intense and non-consecutive, and when trees are located on more water-limited sites. Managers are therefore advised to avoid over-reliance on this species, and to increase species diversity to enhance forest stability.<\/p>","protected":false},"featured_media":41329,"template":"","acf":[],"yoast_head":"\n