Are 40 years better than 55? An analysis of the reduction of forest rotation to cope with drought events in a Douglas fir stand

Abstract

& Key message Reduction of forest rotation is analyzed as a potential adaptation strategy for a Douglas fir stand to cope with drought-induced risk of forest decline. The methodology combines a water balance modeling and an economic approach. Results show that, from an economic perspective, adaptation (immediate or delayed) is always better than the absence of adaptation. & Context Reduction of rotation length emerges as a potential adaptation strategy to cope with climate change. & Aim The study aims to address the reduction of rotation length to deal with the drought-induced risk of forest decline taking a multidisciplinary approach. & Methods We estimate probabilities and impacts of drought events quantified by water balance modeling and we evaluate, from an economic point of view, the reduction of rotation length to cope with the drought-induced risk of forest decline. We compare three different adaptation strategies at the economic level: absence of adaptation, immediate adaptation, and delayed adaptation. & Results Results suggest that immediate reduction of rotation length is associated with the best economic return, followed by delayed adaptation and, finally, by the absence of adaptation. This result is sensitive to the level of timber loss in the event of drought occurrence. If the loss of timber volume is higher than 48%, then delayed adaptation may be preferable to immediate adaptation. & Conclusion Beyond the specificities of the case study, this paper proposes a multidisciplinary approach to address adaptation strategies.

JULES-BE: representation of bioenergy crops and harvesting in the Joint UK Land Environment Simulator vn5.1

“…For rotation forestry, the yield over the 40-year rotation was 41 t C ha -1 for broadleaf and 69 t C ha -1 for needleleaf, equivalent to 1.0 and 1.7 t C ha -1 year -1 , respectively. This is higher than the average productivity for European forests (around 0.8 t C ha -1 year -1 , assuming 250 kg C m -3 of harvested roundwood) (Payn et al, 2015), but lower than recent estimates from France for Douglas fir of 3.1 t C ha -1 year -1 following a 40-year rotation (Bréda and Brunette, 2019). These examples show that with appropriate tuning and validation of the PFT and harvest parameters, JULES-BE could be used to facilitate decision-making on questions such as species selection, harvesting regime, harvest frequency and timing.…”

JULES-BE: representation of bioenergy crops and harvesting in the Joint UK Land Environment Simulator vn5.1

“…Given these difficulties, and the fact that JULES is a global model, accurate average yields with reduced variability compared to observations is likely to be an acceptable compromise for most applications of JULES-BE. The Miscanthus PFT has not been tested with other advanced modules within TRIFFID, such as nitrogen cycling or layered soil carbon (Burke et al, 2017), and will likely require additional updating and tuning of parameters to yield useful results with other functions. Since nitrogen content is recorded for the harvested biomass, with appropriate tuning JULES-BE could also be used to quantify nitrogen loss from bioenergy crop ecosystems due to harvesting.…”

Effect of root and butt rot uncertainty on optimal harvest schedules and expected incomes at the stand level

“…Reducing rotation length might bring other benefits not considered in this study, such as (i) reducing the time to which the damaged forest is exposed to further disturbances such as, for instance, windthrow and stem breakage (Seifert 2007); (ii) provide an earlier opportunity to change the tree species to more tolerant ones (Peri et al 1990); (iii) decrease the damages the rot stored in the root system causes to the next tree generation (Wang et al 2014) and (iv) avoid contamination in a broader spatial scale (Macpherson et al 2016). On the other hand, it might also have a negative effect on carbon sequestration, biodiversity, etc., as mentioned by Bréda and Brunette (2019) and Kaipainen et al (2004).…”

“…Díaz-Yáñez et al (2019) looked into how the risk of snow and wind damage can impact the harvesting ages in spruce forests in Norway. Bréda and Brunette (2019) investigated whether reducing the rotation length in a Douglas fir stand provided a better economic return under drought-induced risk. In all those cases, when the damage is instantaneous and complete, shortening the rotation length is recommended as the best management solution to minimize losses.…”