Woody Control

Control of woody invasives is here to stay. When managing a native ecosystem, plan to spend time on this activity. 

Initial clearing of an Area

The initial clearing of an area is typically done by hand with chainsaws and then treating the cut stumps. Doing it by hand is lighter and gentler on the land than using large, heavy machinery to rip the trees out by their roots. Chainsaw work also does the least amount of disturbance and damage to the native herbaceous understory. It’s easier to ID and keep any native woody understory when working with hand tools. Keeping this structural understory in woods or oak savannas is important for the wildlife.

What to expect after the initial clearing:

  1. Lots of weeds – weeds you didn’t see before – see how to control herbaceous plants.
  2. Lots of unwanted resprouting woodies. Both this and the increased unwanted herbaceous plants will make you feel like you’ve made a really big mistake. This is normal!

Follow up is essential.

Oak savanna before cleared
Oak savanna after restoration work has begun

The photo on the left is before our initial clearing work began. The photo on the right is a year later. It’s the same area, but the right photo is just closer. The oak tree is fully visible now that the invasive understory has been removed.

4 Methods of Follow up

We use these 4 basic methods: Spritzing, Cut & Treat, Swiping, and Foliar Spraying. Which one we choose depends on the situation. This document lists the techniques, the equipment we use, the pros/cons of each, and when they can be used.

Managing expectations

Expect resprouting and follow up after any disturbance.

“Chunk it out” — Divide the land in sections to reduce being overwhelmed. Expect that even this technique will catch you by surprise and you’ll find you’re behind. When that happens, it’s time to triage so you are reducing the spread of seeds. 

Triage

When we run out of time or the area is larger than our human bodies can do in one growing season, we triage by mowing or brushcutting. This can be done in the growing season to ensure they do not produce seeds. We use this method mostly for brambles. It doesn’t kill them but it keeps them from blooming and spreading their seeds. 

Downside: Our unwanted woodies are resprouters and neither of these techniques kill them; it merely kicks the can down the road. But, hey, life gets in the way and sometimes this is our option. 

Can you Burn or Mow your Woodies Away?

NO — is the short answer! The woodies are resprouters. If you don’t take the time to deal with them, each disturbance sends a message to the roots and they send up more stems. Anecdotally, one year, the multiflora on the right was on fire and flaming throughout the burn – ignored it after a burn and back it came with more stems! Ugh!

Mowing could work if you cut the stems repeatedly throughout the growing season. The plant would begin to exhaust its resources. How often one would have to do this and would it be effective in one growing season (or how many years?) is the question. If you’re going to go to this much work, do the Cut & Treat Method!

Honeysuckle that flamed throughout a burn yet resprouted
Honeysuckle that flamed throughout a burn yet resprouted

Some considerations with fire:

  1. Like mowing, it would require repeated applications throughout the growing season. For how many years is unknown. 
  2. Fire could possibly kill some of the very small resprouters, but it shouldn’t be counted on to do this. The resprout would need to be sufficiently small and the fire sufficiently hot. What is “sufficient” – who knows. It’s nature. There’s no way to quantify this so it’s meaningful to a landowner.
  3. Annual burns are touted as the answer yet they don’t leave enough fuel to create a hot enough fire to any anything but damage resprouters, which means they will come back en force.  Annual 100% burning of the same area creates more problems than they solve: more frequent fire reduces biodiversity and it means every year you are killing all the insects in that area that are not within the soil. The collateral damage is high and it doesn’t reduce the unwanted resprouters.
  4. Dormant season burns are equally as ineffective because the combination of the size of woody growth and fire heat isn’t known.
  5. Growing season burns may topkill the unwanted woody but don’t expect it to kill it. It will also damage your native herbaceous growth.

Resprouting Examples

Below are photos of various unwanted invasives, each resprouting after a fire. The middle one was taken before the char on the stem wore off. I learned not to be fooled by a blackened stem; it doesn’t indicate the plant was killed by the fire. In some cases, it may not have damaged that particular stem either. 

Resprouting woody after a burn
Resprouting woody after a burn
Resprouting woody after a burn

Topkilled after a Burn; NOT DEAD!

To the right are 3 photos of topkilled plants. They all look like they were killed and are dead, but looks are deceiving. If you make the mistake of assuming these are dead and don’t do the follow up, you’ll find these unwanted, resprouting woodies have bulked up their root systems and will be ready to put on a show you don’t want to see next year!

Topkill example
Topkill example
Topkill example