Delaware census: Street tree do’s and don’ts

Two crews of six Delaware County Mas­ter Gar­dener Vol­un­teers are hit­ting the streets of Delaware weekly in this, the third year of the ongo­ing Delaware Tree Cen­sus. The teams have com­pleted the inven­tory in the cen­tral city and they are now work­ing in the newer devel­op­ments on the out­skirts of town. As they progress, they have noted many beau­ti­ful, healthy trees, while oth­ers are strug­gling. They even encounter trees that are dead or dying.

As a home­owner, there are some things that you can do to help your street trees live up to their best poten­tial. Accord­ing to Chuck Rex­ode, a retired USFS research ento­mol­o­gist and the city’s con­tract forester for 22 years, the two most impor­tant things you can do are to water your trees dur­ing drought peri­ods like we have had this sum­mer, and to stop vol­cano mulching.

Many trees are stressed from lack of rain­fall. Rex­ode noted that the sit­u­a­tion is dire for many young sugar maple trees with sun scald. This con­di­tion occurs when water evap­o­rates from the leaves faster than the roots take it up. Water­ing will help and may be enough to save the tree. Remem­ber when you water to give the ground under the tree canopy a good soak­ing so the water will pen­e­trate the ground for sev­eral inches.

Many home­own­ers and land­scap­ers pile mulch around the trees. Accord­ing to Rex­ode, this is a bad prac­tice as excess mulch pro­motes fun­gal growth around tree trunks and then decay sets in. Also, a wet spring sea­son pro­motes root growth around the base of the tree in the mulch, but these roots dry out quickly later in the sea­son and the tree suf­fers since it depends on these newly formed feeder roots. The roots in the mulch can also grow around the tree trunk and end up stran­gling it. While you should keep mulch around a tree year-round, it should only be a cou­ple of inches deep. The mulch helps avoid string trim­mer and lawn mower dam­age, but it should be kept two to three inches away from the trunk to avoid encour­ag­ing fun­gal growth. Home­own­ers also should reg­u­larly remove suck­ers, which are small shoots that grow out from the base of the tree trunk.

Many street trees need prun­ing. But, Rex­ode cau­tions, “Don’t prune unless you know how to do it prop­erly.” The city’s Shade Tree Com­mis­sion is seri­ously con­sid­er­ing launch­ing a new pro­gram to help the city prune its street trees. It would be staffed by groups of trained vol­un­teers that would prune their own street trees and/or street trees in their sub­di­vi­sion. This effort would be lim­ited to trees with branches that can be pruned man­u­ally, with­out the use of power tools and are close enough to the ground that they can be reached with­out the use of a ladder.

Some­times trees are planted at an incor­rect depth and that can lead to pre­ma­ture decline or death. At the base of the tree where the trunk and the root sys­tem meet is the root col­lar, which has a slight flare. The flare needs to be exposed when the tree is planted. Accord­ing to Erik Draper from OSU Exten­sion, “Plant ’em high — watch ’em die; Plant ’em low — never grow; Plant ’em right — sleep at night!”

Land­scap­ers or devel­op­ers fre­quently stake new trees to ensure they remain upright. Rex­ode said these stakes should remain around the trees for the entire war­ranty period of two years. While one year would be suf­fi­cient in most cases, devel­op­ers and land­scap­ers will not war­ranty the trees if the stakes have been removed. These stakes should not be exces­sively tight and should allow for some tree move­ment. After the war­ranty period, the stakes and guy wires should be removed. If left on per­ma­nently, the wires will even­tu­ally com­pletely gir­dle the tree, depriv­ing it of nutri­ents, includ­ing water, and the tree will decline or die.

Delaware City is imple­ment­ing a new pro­gram to increase the diver­sity of the street trees. The city is also par­ing back, but not elim­i­nat­ing, plant­ing maple trees. Maples already rep­re­sent a large per­cent­age of Delaware’s urban for­est. In addi­tion, maple trees are dis­posed to ver­ti­cil­lium wilt and more recently there has been the threat of the Asian Long­horned Bee­tle (ALB), which has been found in south­west Ohio. Since insect pests typ­i­cally attack one tree genus, or fam­ily, increased tree diver­sity will help avoid a sit­u­a­tion where the major­ity of the street trees in one com­mu­nity are destroyed.

As of early August 2012, Delaware County Mas­ter Gar­dener Vol­un­teers have com­pleted about two-thirds of the city’s dis­tricts in the Tree Cen­sus, and they expect to com­plete the project in 2013. You may see a group of “tree hug­gers” in your neigh­bor­hood iden­ti­fy­ing and mea­sur­ing trees. Please don’t hes­i­tate to say “Hi” or ask them a question.

Nancy F. Traub is an OSU Exten­sion Delaware County Mas­ter Gar­dener Volunteer

Posted by Master Gardener on Aug 10 2012. You can follow any responses to this entry through the RSS Feed. Comments can be made below.