TDUK SupplyingTimber Issue 8 DIGITAL - Magazine - Page 28
———— FORESTRY MANAGEMENT ————
SUPPORTING SOIL HEA
WELL-MANAGED PINE F
Abodo explores how New Zealand’s approach to forestry has
changed over the past generation and how well-managed
plantation forests can maintain or improve soil health.
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"I’ve always believed planted
forests were going to be
important to New Zealand,”
says Peter Clinton, Principal
Researcher at Scion, the New
Zealand Forest Research
Institute.
New Zealand’s diverse
soil types are generally
naturally acidic, with planted
forest soils providing many
important bene昀椀ts including
the growth of timber and
昀椀bre, carbon sequestration,
providing habitats for a
variety of biodiversity, 昀椀ltering
groundwater and regulating
昀氀ooding.
Peter says: “We’ve studied the
nutrient uptake and demand
on these sites for more than
30 years and have found that,
depending on how trees are
harvested, we can control the
quantity of nutrients removed.
“We’ve also done experiments
on how harvesting intensity can
impact long-term productivity,
and we’ve already seen many
of these plantation sites go
through a second rotation
without any loss of productivity.
In the case of Kaingaroa Forest,
we’re heading into a fourth
rotation, with planted trees
growing there now for about 100
years.”
Throughout their full lifecycle,
plantation forests and natural
forests can withstand a similar
level of soil disturbance.
“Natural forests undergo quite
catastrophic disturbances at
times, through weather events
SUPPLYING TIMBER
28
SPRING 2025
that might see trees topple
and root plates come out of
the ground. But they recover.
The same is true of the soil
disruption caused by harvesting
in planted forests. Soil is robust
– if you don’t burn it, you won’t
typically see a big nutrient shift.
“In some cases harvesting
can be bene昀椀cial, as it brings
unweathered material and
subsoil to the surface. That
process happens naturally as
part of forest management.
The other thing that happens is
nutrient cycling, where you will
see nutrients entering a forest
with rain or dust. There are lots
of natural processes going on
