Monday, May 20, 2013

Jug-what? Juglone!

Post contributed by David from Conservation Corps Youth Outdoors Crew 2:

Have you strolled along Como Lake recently and seen some black patches in the grass? Well fear not that wasn’t the work of some pyromaniac prankster, but rather a prescribed burn done for the benefit of the plants. Many of the plants found along the Como lake shoreline are native wildflowers and grasses that occur naturally in areas that experience burns every 3-5 years. Since it would be unsafe to allow fires to occur naturally in a city park, we get to come in and administer a prescribed burn to give those plants just what they need but in a safe, controlled environment. Burns are beneficial for many reasons; some of which being that they quickly return nutrients to the soil, remove dead plant matter that could choke out new growth, and kill back non-native plants that just can’t handle the heat.

While preparing for the burn we also ran into the DNR’s local non-game wildlife specialists. They were at Como Lake setting up turtle traps for a future educational activity. Animal traps are often set up by wildlife scientists to help them learn what animals live in the area. As they set up the traps they used sardines as bait and as soon the sardines hit the water we saw turtles peaking up on the surface.

We also have continued to plant more trees down along the Crosby Lake floodplain. This week we planted 500 black walnut and burr oak trees. Black walnuts are interesting trees because they produce a natural herbicide in their roots called juglone. Juglone is an example of an allelopathic compound that inhibits plant growth, meaning the black walnut tree has found its own natural way to beat back competition! Although black walnut is a native tree and in this case its allelopathic effect works in our favor, other less desirable plants, such as garlic mustard have shown to also create their own allelopathic compounds. This is one reason why when garlic mustard is introduced to an area it can quickly take over in huge mats. That’s where our strong arms come in to pull them out!