HAL Id: hal-02793549
https://hal.inrae.fr/hal-02793549
Submitted on 5 Jun 2020
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Effects of tree species diversity on resistance to natural disturbances in planted forests
Herve Jactel, Johanna Boberg, Damien Bonal, Bastien Castagneyrol, Barry Gardiner, José-Ramon Gonzalez, Julia Koricheva, Nicolas Meurisse, Eckehard
Brockerhoff
To cite this version:
Herve Jactel, Johanna Boberg, Damien Bonal, Bastien Castagneyrol, Barry Gardiner, et al.. Effects of tree species diversity on resistance to natural disturbances in planted forests. 5. International Eco- Summit. EcoSummit 2016. Ecological Sustainability: Engineering Change., Aug 2016, Montpellier, France. 26 p. �hal-02793549�
Effects of tree species diversity
on resistance to natural disturbances in planted forests
Hervé Jactel, Johanna Boberg , Damien Bonal, Bastien Castagneyrol, Barry Gardiner, José-Ramon Gonzalez, Julia Koricheva, Nicolas Meurisse,
Eckehard Brockerhoff
http://www.waldwissen.net
An urgent need for new, planted forests
1. to meet the social demand for wood products including energy wood
2. to contribute to climate change mitigation through carbon sequestration
3. to alleviate the logging pressure
on natural forests and preserve biodiversity
Rising threats due to global change
1.
Climate change
↗ temperatures trigger pest outbreaks and range expansion
2006 1979 2011
Pine processionary moth
Mountain pine beetle
Rising threats due to global change
1.
Climate change
↗ droughts increase the risk of forest fires
↗ droughts increase tree susceptibility to infection
Rising threats due to global change
1.
Climate change
↗ wind damage
Rising threats due to global change
2.
World trade
↗ globalization results in more biological invasions
Exotic arthropods
N u m b er n ew s p e c ie s / ye ar
Dryocosmus kuriphilus
Origine: China
Challenge: design new planted forests less vulnerable on the long term
• Trees are being planted for decades or centuries
• Forests will experience disturbances never met before
Is mixing tree species in planted forest an option?
•
Diversity – resistance relationships in grasslands
Resistance of mixed forests to 7 natural disturbances
1.
Patterns of response to tree diversity
2.
Underlying ecological mechanisms
1.
Drought
2.
Fire
3.
Windstorm
4.
Mammal herbivores
5.
Pest insects
6.
Fungal pathogens
7.
Invasive species
William M. Ciesla, Forest Health Management International, Bugwood.org
http://www.redbubble.com/people/bberwyn
1. Resistance of mixed forests to drought
Water Use Efficiency = Productivity / Transpiration
http://dnr.wi.gov/
2. Resistance of mixed forests to fires
Light Severe
http://www.sierraforestlegacy.org
3. Resistance of mixed forests to windstorms
http://iireporter.com
4. Resistance of mixed forest to mammal herbivores
Contrasting effects on mammal herbivores
-150%
-100%
-50%
0%
50%
100%
150%
200%
36 % less damage in mixed forests
(80% cases)
5. Resistance of mixed forest to pest insects
119 case studies, 33 tree species
-31%
6. Resistance of mixed forest to fungal pathogens
Overall better resistance of mixed forests to root rot fungi
Resistance or neutral effects for foliar pathogens
7. Resistance of mixed forests to invasive species
M ea n % d ef o lia ti o n p er p lo t
Tree species richness
- 42% - 15% 0%
Resistance of mixed forests: common features
1.
Direction and magnitude of effects depend on pest specialization
Castagneyrol et al. 2014
-
Spill over
-
Mixing diet
Resistance of mixed forests: common features
2.
Forest composition more important than tree species richness
-60%
-50%
-40%
-30%
-20%
-10%
0%
% d a m a g e re d u ct io n
conifer conifer
broadl.
broadl.
broadl.
conifer
conifer broadl.
– 27%
– 45%
Resistance of mixed forests: common features
3.
“Associational resistance” operate at several, nested spatial scales
Tree scale
Neighbors identity
Stand scale
Species composition
Landscape scale
Heterogeneity
Mechanisms underlying
diversity – resistance relationships
0. The insurance hypothesis
Being composed of several species with different functional traits,
mixed forests have a higher likelihood of containing resistant trees,
thus providing more opportunities to maintain a forest cover
and sustain basic ecosystem functions on the long term
Mechanisms underlying
diversity – resistance relationships
1.
Traits complementarity
-
Root depth / drought
-
Bark anatomy / fire
-
Crown architecture / wind
-
Leaf quality / herbivores
-
Niche occupancy / invasive species
Mechanisms underlying
diversity – resistance relationships
2.
Reduced density (amount) of susceptible trees
-
herbivores less likely to enter the plot
-
lower amount of resources/fuel
-
longer distance between host trees
Gerlach et al. 1997
T re e m o rt al it y d u e to A . o st o ya e in m ix ed s ta n d s
Mechanisms underlying
diversity – resistance relationships
3.
Reduced probability of susceptible trees being hit
Spruce - Fir Beech - Maple
B ro w s in g f re q u e n c y
Saplings planted
under Eglantine
-
physical protection by neighbors
-
diversion (decoy) processes
Mechanisms underlying
diversity – resistance relationships
4.
Reinforced multitrophic interactions
100% Scots pine
50% Scots pine – 50% Birch
Neodiprion sertifer
-
decomposers and mycorrhiza
-
