Got Nature? Blog

Purdue Landscape Report: Temperatures are finally dropping and leaves are changing color. Autumn is progressing well in my opinion. Before you know it winter will be here, and some people will be wondering is there anything to be done to better protect the trees around you?  The answer is yes, and I applaud you for your initiative to continue caring for your trees. To give your trees the best chance to survive the winter and better thrive next year there is an assortment of activities available ranging from diy projects up to calling in an ISA certified arborist to help you out.

Figure 1. Maintenance of trees in the fall include many tasks before dormancy occurs.

Mulching:
One simple task to better prepare your trees for winter is to add a new layer of mulch, which benefits your trees in multiple ways. Adding a 2-3 inch thick layer of mulch will better maintain moisture levels and buffer extreme temperature changes in the soil and will add some organic matter too. Mulching to the drip line will benefit the tree the most, but in the case of larger trees it’s not always feasible. Try for at least a 3-foot radius from the trunk and make sure to leave a 2 inch or so gap between the trunk and the mulch. Remember, no volcano mulching.

Fertilizing:
That mulch you just added will add some organic material to your soil as it slowly breaks down, but an autumn fertilization can benefit your trees too. Unlike trees in the forest that have a natural supply of nutrients from fallen leaves and twigs, trees around our homes are usually deprived as we rake and clean up our yards. Adding a slow-release fertilizer in the fall helps provide a nutrient boost over the winter, can promote root growth, and better prepare your tree for Spring.

Watering:
Water is still an essential part of your tree care plan, but as temperatures drop and trees begin to head into dormancy they don’t need as much water as is required in the hit summer months. If you have irrigation systems in your yard start to drop the frequency of watering. You can water up until the first freeze, but make sure soils are just a little damp and not soaked. Evergreens in particular will benefit from slow deep watering 1-2 times a week until the soil freezes. Winter winds and temperatures can desiccate the needles without an adequate supply of water.

Pruning:
Now is a good time to prune out any dead, damaged, or diseased limbs in your trees. If you have access to hand saws and pole saws or pruners, you can remove smaller branches or those closer to the ground. Make sure you are making proper pruning cuts though, and if there are large limbs, those at heights, or you are just unsure of how to make a good cut enlist the help of a professional arborist.

Trunk damage:
Sunscald or southwest damage occurs on young and/or thin barked trees in the winter. Wounds can occur between the south to southwest facing part of the trunk on sunny days in the winter as temperatures rise and suddenly drop. Over time these wounds can become quite large. Trees can also incur damage from deer during the rut. Bucks will scrape trees with their antlers, scraping off the bark and damaging the cambium. Both of these injuries can be reduced one younger trees by installing tree guards in the fall. Tree guards are plastic barriers you place around the main stem of the tree. I recommend using white corrugated drainage pipe that can be found at most home centers. You can make a cut lengthwise along the pipe for easy installation and make sure it has a large enough diameter to leave a space between it and the tree. Just remember to remove it come Spring.

Inspections:
Visual inspections can be done year-round, but this time of the year it might be easier to see changes in your tree as leaves are falling and the canopy becomes more visible. From the ground up to the canopy, some of the things you’re looking for include fungal growth around the base of the tree, any sort of damage on the main stem or branches, premature leaf drop or color change, and branches that are dead, cracked, diseased, or seem weak. Any concerns you find are also great information to share with an ISA Certified arborist which can be found using the Trees Are Good website.

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Resources:
Re-mulch Your Trees, Purdue Landscape Report
Pruning, Purdue Landscape Report
Southwest Damage/Sunscald, Purdue Landscape Report
Planning the Tree Planting Operation, The Education Store, Purdue Extension’s resource center
Tree Risk Management, The Education Store
Tree Planting Part 2: Planting Your Tree, The Education Store
Planting Your Tree Part 1: Choosing Your Tree, Purdue Extension – Forestry and Natural Resources (FNR) YouTube Channel
Summer Tree Care, Purdue Landscape Report
Tree Defect Identification, The Education Store
Tree Wound and Healing, Got Nature? Blog, Purdue Extension – FNR
Surface Root Syndrome, The Education Store
Shrubs and Woody Vines of Indiana and the Midwest, The Education Store
Ask an Expert: Tree Selection and Planting, Purdue Extension-FNR YouTube playlist
ID That Tree, Purdue Extension-FNR YouTube playlist
Subscribe – Purdue Extension-FNR YouTube Channel

Ben McCallister, Urban Forestry Specialist
Purdue Forestry & Natural Resources