Top of Austrian Pine turning brown - Ask Extension
Hi, I live in north Golden. I have about 10 austrian pines in my yard. On 3 or 4 of them the top of the tree has turned brown and looks to be dead...
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Top of Austrian Pine turning brown #631826
Asked May 05, 2020, 10:53 PM EDT
Hi, I live in north Golden. I have about 10 austrian pines in my yard. On 3 or 4 of them the top of the tree has turned brown and looks to be dead. This is also occurring with many of the neighbors Austrian pines in our subdivision. Some one told my it was caused by a gypsy moth and I could spray the tree. Do you think this is the case or is it something else? Thank you.
Jefferson County Colorado
Expert Response
Hello!
There are two primary possibilities which come to mind:
1) Winter burn
2) Pine Tip Moths (can investigate this possibility by looking for what we can see in Figure 5. of this document: https://extension.colostate.edu/docs/pubs/insect/05529.pdf)
We have been seeing trees throughout the region with cases of winter injury. Given that multiple neighbors are seeing very similar damage, my thoughts first go to Winter burn/desiccation/injury.
There are two primary possibilities which come to mind:
1) Winter burn
2) Pine Tip Moths (can investigate this possibility by looking for what we can see in Figure 5. of this document: https://extension.colostate.edu/docs/pubs/insect/05529.pdf)
We have been seeing trees throughout the region with cases of winter injury. Given that multiple neighbors are seeing very similar damage, my thoughts first go to Winter burn/desiccation/injury.
If Winter burn is the cause, no treatment is required other than regular water during the growing season, and monthly water during the fall and winter when there has been no precipitation for 3-4 weeks and temperatures are over 40F.
- Check the new buds on the branch tips to see whether they are still alive. To check them, gently feel them to see whether they are plump with some give, or whether they are dry and brittle. You can cut into an inner bud that you don't mind losing to see whether it is still alive and green inside. If the buds are alive, watch and wait for them to candle out.
- Wait and watch to see which ones candle out; prune out dead branch tips in mid-summer after new growth has emerged. Over the next few seasons, tree growth will fill in any gaps left by pruning.
- To help protect trees against future sudden temperature drops in fall, and over the winter, hand water monthly when there has not been precipitation and temps are above 40F. In anticipation of a temperature drop, a good soaking to get moisture down 12+ inches will help the tree protect itself. Add 3-4 inches of mulch (pine needls or shredded bark, keeping mulch 2-4 inches away from the trunk) under the tree out to the drip line to moderate moisture and temperature changes around the roots.
References:
- CO State Forest Service - winter burn https://csfs.colostate.edu/2020/04/26/ponderosa-pines-spruce-may-exhibit-winter-burn-damage/
- Winter Browning of Evergreens https://planttalk.colostate.edu/topics/weeds-cultural-problems/2114-winter-browning-evergreens/
- Environmental Disorders of Woody Plants (see drought and frost injury) https://extension.colostate.edu/docs/pubs/garden/02932.pdf
- Fall and Winter Watering https://extension.colostate.edu/docs/pubs/garden/07211.pdf
