#1 Japanese Knotweed
​

As you arrive into the carpark and look left towards the lake the mass of greenery (7 to 8 feet tall) is Japanese Knotweed. As the name suggests it originally evolved in Japan and is the first plant to colonize the slopes of volcanoes following an eruption. It grows and spreads very rapidly such that it outcompetes any native plants. Native animals (including deer) don’t eat it and diseases and insects have little to no impact. If you look to the ground  under the plants there are virtually no other plants surviving. This result is a classic example of what invasive plants can do –  eliminate the competition and destroy the biodiversity.

#2 Wisteria 
(Chinese and Japanese origins)

This vine is a favorite for many gardeners but in forests it destroys trees by strangulation, blocking light from the leaves and absorbing the nutrients and water from the roots. The result is that the trees eventually die and fall over or are weakened such that they are more easily blown over by the wind or snow. The wisteria survives and spreads all over the ground from the fallen trees and from the millions of seeds that it produces. The dense ground cover stops native tree seedlings from establishing so the whole area becomes a monoculture of wisteria. It is a poisonous plant which explains why deer don’t eat it. The deer do however continues to eat the native plants so the net effect of wisteria and deer foraging is total destruction of the native forest habitat.

What can be done about invasive plant species?

Different invasive plants can be controlled or minimized by various techniques. Experts in the field have experimented with various techniques with the objectives of gaining control with minimum damage or contamination to the environment and selective encouragement of native plant species. The overall approach is often described as “Habitat Restoration” but a key element of any approach must include a management strategy to limit the number of deer.
Picture
Deer Management At Brightwood
Deer contribute directly and catastrophically to the problem of invasive species.  By preferentially eating only the native plants, they give non-native plants a huge survival boost.  The deer population has grown extensively in recent years, accelerating the the destruction of the native Brightwood habitat.  No restoration project can be contemplated without a plan to remove the deer from the park.