Most of the 7500 native forest fragments in the Waikato region are on privately owned pastoral land. Most are not fenced, and are regularly damaged by stock. The first priority for all forest fragments should be to keep stock out of them permanently.
On this page: Stock damage, Benefits of fencing, Fencing tips
Unfenced fragments on farms can suffer a lot of damage from livestock. New Zealand’s plants and animals evolved without any large grazing mammals. Our soils and plants can’t cope with the trampling, grazing and waste from stock.
Cattle, goats and, to a lesser degree sheep, with free access to a fragment will heavily graze edible native seedlings and saplings, opening up the forest underneath. Livestock can also weaken, and sometimes kill trees by rubbing against trunks and trampling roots. Fragments continually visited by stock will become a stand of sick, old trees, with no young plants to replace those that die out. Eventually the whole fragment will collapse.
Damage from livestock can also decrease the water quality of fragment streams, affecting the animal life within them.
However, stock damage may increase the risk of fire as vegetation under the trees is eaten. The area can become open, breezy, and dry with an increased build-up of broken branches and dead trees. Keeping stock out may result in weed growth, but most non-invasive weeds will die within a few years as native plant growth blocks out their light.
Some Waikato farmers have discovered that keeping livestock out of forest fragments benefits both the fragment, and farm management overall.
Fencing stock out of forest fragments:
Keeping stock out of waterways that pass through fragments:
Healthy, ungrazed forests have dense native undergrowth, a deep leaf litter layer, and thick shrub, sedge or flax margins. They filter out sediments and nutrients from rainwater and water running off from surrounding land, and reduce erosion during heavy rain. Fragments with an open understorey and bare earth can’t do this, and may, in fact, contribute to the loss of sediment.
Find out more about how grazing affects wetlands.
We provide advice and support for efforts to reduce the impacts of farming on waterways through fencing and planting waterway margins. Find out more about our integrated catchment management services(external link).
Here are some suggestions to help you protect your fragment from stock:
For fragments which are small, open underneath, and/or exposed to wind:
Shelter for stock is important, but with a tall forest stock can seek shade beside, rather than inside the forest. You could leave a few trees outside the fence, at least until shelter trees in the paddock are big enough.