Abstract
Aim: Anthropogenic fires caused New Zealand's temperate rain forests to decline rapidly from 80% to 50% cover after Polynesian arrival. In contrast, Australian temperate rain forests have remained stable in spite of a longer history of fire and human occupation. We evaluate whether New Zealand's conifer-dominated forests declined because they lack fire resistance traits. We predicted that New Zealand species should have thinner bark than their Australian counterparts, and slower growing conifers should have relatively thicker bark than angiosperms.
Location: Temperate rain forests of south-eastern Australia, Tasmania
and New Zealand.
Methods: We examined the ratio of bark thickness to stem
diameter (relative bark thickness) as a standardized index (by tree size) of
fire resistance. Nonlinear power models were fitted to examine trends in
relative bark thickness between trees from New Zealand and Australia. Bark
thickness was also compared between species pairs and congeners and by
phylogenetically corrected ANOVA.
Results: Although angiosperms and gymnosperms in New Zealand had thin
bark in a global context, they had significantly thicker bark than their
Australian counterparts. Bark thickened more rapidly for small trees in New
Zealand but declined with increasing stem diameter. Allocation to bark
thickness was greater for larger stems in Australia. New Zealand gymnosperms
had the thickest bark of all species examined.
Main
conclusions: Fire resistance is a complex syndrome comprising
functional traits that ensure protection (resistance - bark) from and recovery
(resilience - resprouting) after fire. Thin bark in temperate rain forests
suggests weak selection by fire on bark traits. However, the stability of
Australian temperate forests in a flammable landscape emphasizes the importance
of resprouting, especially basal resprouting, to forest persistence after fire.
New Zealand forests do not resprout after fire and lack the fire resistance
traits required for recovery from repeated anthropogenic fires.
| Original language | English |
|---|---|
| Pages (from-to) | 1467-1477 |
| Number of pages | 11 |
| Journal | Journal of Biogeography |
| Volume | 41 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2014 |
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Bark thickness does not explain the different susceptibility of Australian and New Zealand temperate rain forests to anthropogenic fire. / Lawes, Michael; Richardson, Sarah; Clarke, Peter J; Midgley, Jeremy J; McGlone, Matt; Bellingham, Peter.
In: Journal of Biogeography, Vol. 41, No. 8, 2014, p. 1467-1477.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Bark thickness does not explain the different susceptibility of Australian and New Zealand temperate rain forests to anthropogenic fire
AU - Lawes, Michael
AU - Richardson, Sarah
AU - Clarke, Peter J
AU - Midgley, Jeremy J
AU - McGlone, Matt
AU - Bellingham, Peter
PY - 2014
Y1 - 2014
N2 - Aim: Anthropogenic fires caused New Zealand's temperate rain forests to decline rapidly from 80% to 50% cover after Polynesian arrival. In contrast, Australian temperate rain forests have remained stable in spite of a longer history of fire and human occupation. We evaluate whether New Zealand's conifer-dominated forests declined because they lack fire resistance traits. We predicted that New Zealand species should have thinner bark than their Australian counterparts, and slower growing conifers should have relatively thicker bark than angiosperms. Location: Temperate rain forests of south-eastern Australia, Tasmania and New Zealand. Methods: We examined the ratio of bark thickness to stem diameter (relative bark thickness) as a standardized index (by tree size) of fire resistance. Nonlinear power models were fitted to examine trends in relative bark thickness between trees from New Zealand and Australia. Bark thickness was also compared between species pairs and congeners and by phylogenetically corrected ANOVA. Results: Although angiosperms and gymnosperms in New Zealand had thin bark in a global context, they had significantly thicker bark than their Australian counterparts. Bark thickened more rapidly for small trees in New Zealand but declined with increasing stem diameter. Allocation to bark thickness was greater for larger stems in Australia. New Zealand gymnosperms had the thickest bark of all species examined. Main conclusions: Fire resistance is a complex syndrome comprising functional traits that ensure protection (resistance - bark) from and recovery (resilience - resprouting) after fire. Thin bark in temperate rain forests suggests weak selection by fire on bark traits. However, the stability of Australian temperate forests in a flammable landscape emphasizes the importance of resprouting, especially basal resprouting, to forest persistence after fire. New Zealand forests do not resprout after fire and lack the fire resistance traits required for recovery from repeated anthropogenic fires.
AB - Aim: Anthropogenic fires caused New Zealand's temperate rain forests to decline rapidly from 80% to 50% cover after Polynesian arrival. In contrast, Australian temperate rain forests have remained stable in spite of a longer history of fire and human occupation. We evaluate whether New Zealand's conifer-dominated forests declined because they lack fire resistance traits. We predicted that New Zealand species should have thinner bark than their Australian counterparts, and slower growing conifers should have relatively thicker bark than angiosperms. Location: Temperate rain forests of south-eastern Australia, Tasmania and New Zealand. Methods: We examined the ratio of bark thickness to stem diameter (relative bark thickness) as a standardized index (by tree size) of fire resistance. Nonlinear power models were fitted to examine trends in relative bark thickness between trees from New Zealand and Australia. Bark thickness was also compared between species pairs and congeners and by phylogenetically corrected ANOVA. Results: Although angiosperms and gymnosperms in New Zealand had thin bark in a global context, they had significantly thicker bark than their Australian counterparts. Bark thickened more rapidly for small trees in New Zealand but declined with increasing stem diameter. Allocation to bark thickness was greater for larger stems in Australia. New Zealand gymnosperms had the thickest bark of all species examined. Main conclusions: Fire resistance is a complex syndrome comprising functional traits that ensure protection (resistance - bark) from and recovery (resilience - resprouting) after fire. Thin bark in temperate rain forests suggests weak selection by fire on bark traits. However, the stability of Australian temperate forests in a flammable landscape emphasizes the importance of resprouting, especially basal resprouting, to forest persistence after fire. New Zealand forests do not resprout after fire and lack the fire resistance traits required for recovery from repeated anthropogenic fires.
KW - anthropogenic effect
KW - bark
KW - coniferous forest
KW - environmental disturbance
KW - forest fire
KW - population decline
KW - rainforest
KW - temperate forest
KW - Australia
KW - New Zealand
KW - Polynesia
U2 - 10.1111/jbi.12292
DO - 10.1111/jbi.12292
M3 - Article
VL - 41
SP - 1467
EP - 1477
JO - Journal of Biogeography
JF - Journal of Biogeography
SN - 0305-0270
IS - 8
ER -