possum damage to forests pen holland. introduction new zealand region site tree leaf interest...
TRANSCRIPT
The field assessment
Browse damage Proportion of leaves chewed
Foliage cover index Fraction of sky blanked out
F = 0.45?D > 0.25 &
D ≤ 0.5F = 0.35?
Still alive
Trees have leaves
Leaf life span
Consumption rate
Foliage biomass
which grow and fall offand sometimes get eaten
Whole/browsed foliage biomass
Predicting tree mortality
Leaf life span
Consumption rate
Canopy healthFoliage Cover Index
Browse damage
Whole/browsed foliage biomass
Foliage biomass
as a result of possums eating leaves
Predicting site mortalityHow many
kamahi trees of what size at
this site?
How do I like to
distribute my
feeding among kamahi trees?
How many possums are
there?
Predicting site mortalityCoombs Rotorangi
Number of kamahi per hectare 200 100
Sample of dbh sizes (mean) 26 cm 32 cm
Kamahi showing no browse 65% 27%
Possum trap catch index 32.8% 44.7%
Coombs Rotorangi
Summary
Model of leaf turnover and possum consumption parameterized for kamahi using field data and literature
Prediction of tree mortality at a new site only required a single site visit for data collection
Looking forwardHow many
kamahi trees of what size at
this site?
How do I like to
distribute my
feeding among kamahi trees?
How many possums are
there?
Looking forward
How many trees of what size and species at this
site?
How do possum populations
change through time?
Why do I like to
distribute my feeding among any
trees? When will I stop and
feed elsewhere?