Spring Cleaning

"Can I prune my trees despite recent, unusual weather fluctuations?"

"How would pruning affect drought-stressed trees?"

These are some recent questions we've been getting as people are feeling the warmer weather and thinking of tidying up their homes and gardens, something we all like to refer to as spring cleaning.

While pruning could cause further unnecessary stress on your trees if done incorrectly, Bal Rao, Davey's research and technical development manager, says minimal pruning, such as creating air tunnels in the canopy to help trees withstand storms, is acceptable.

Drought Check. When it comes to drought, before deciding whether to prune your drought-stressed tree, first remove excess leaves. If moisture is present, growth will remain and buds will emerge. Also evaluate the tree's surroundings, such as sidewalks, buildings and other obstructions, and the value of the limbs in question.

Rao uses three levels to determine the value of tree roots and branches:

• No value: Limbs are dead, broken or hazardous. Prune them at any time - you will not harm the tree.
• Low value: Limbs are typically crossing or rubbing branches, or co-dominant branches that are the same size. Prune these with caution, keeping safety and tree health in mind.
• High value: Limbs are often found on healthy, good-looking trees. Prune these only for cosmetic reasons.

Pruning Pointers. In general, never prune more than 25 percent of your tree's foliage at one time. "In theory, you are making the tree 25 percent less efficient by reducing the photosynthesis surface," Rao says. In some cases, cabling and bracing might be better for your tree than pruning.

But if pruning is necessary, a few guidelines can help you protect your trees from further damage:

• Prune during active growth periods to allow trees to heal themselves at the wounds. "You don't want to slow down the 'walling off' process," Rao says.
• Prune with sharp, clean tools to make small, clean cuts. Disinfect tools with rubbing alcohol.
• Only prune dry trees with angled cuts to help the water drip from the branches. Wet branches can spread disease if spores are present.
• Avoid pruning branches that connect at a V-shaped crotch.
• Remember that topping gives trees weak branching.
• For trees with summer blossoms, prune them in winter before the buds break.

Some trees prefer to be pruned during certain times of the year, so check with your local, licensed arborist for advice.