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Home My WebLink About2003 02 12 Attached Distributed by Mike Mingea (3)Date: February 12, 2003 ATTACHED DISTRIBUTED BY MIKE MINGEA, CITY ARB ORI S T F~D%b Ql~°~ ~~ ~~3 Florida Arborist A Publication of the Florida Chapter ISA x Winter 200 Tree Provenance....7.uhere the heck is t~~t? ~, . ~Mn This Issue: ~jree Provenance` Mulch Ado. President's Message in the News Education Schedule ~~:: Palm Shaving New Members ~.. ;' ;~,osing Farmland to 'Sprawl ~r Chapter 14-40 Ob'server's Bark Certification Exdm ;Schedule 1 1 By: Rick K Joyce As we look at methods to improve tree estab- lishment in ornamental landscapes or ecologi- cal restoration projects, an issue that has been commonly overlooked is the origin of a specific tree. The place of plant ..origin is called the plant or tree provenance. This is the real case of "Who's your 3' Daddy?" 4 5 6 lz 14 15 '`We-_ arecons more land per per- son than at ~uiy tune, in the most wasteful ~'dy, ~~ I~zlp{i Grossi (please see article, Tito `, . ~crn of Firm I,nst to .+~~?~?url ~scb ~l~inute, page ~ ~~~s,~ a '~ ~ a 3 t l 1 :. Tree provenance reflects on the thousands of years a tree species has pioneered a beginning, gone through succession and ultimately colonized an area. The genotypes that were adapted to the conditions (e.g., soil, water, cli- mate, elevation) succeeded, and those that poorly or couldn't adapt failed. Those trees that have adapted to specific conditions and reflect the genetic makeup are called localprov- enance. The location where the ancestors of a specific tree have evolved and live directly in- fluences the specific tree's ge- neucs. The origin of the seed can have an effect on successful estab- lishment of the tree in the landscape. The best example I use in teaching a landscape design class is the red maple (Acer rubrum) tree. The red maple range map on page 12 and the following description gives you the fiill range picture Red maple is one of the most abundant and widespread trees in eastern North America. It grows from southern Newfoundland, Nova Tree Provenance, rnntinued on page 12 .Mulch ado about. nothing? By Chuck Lippi, Extension. Director and Horticulturist, Flagler County This it the second of the series on mulch for Florida landscapes How and Where to Apply Mulch Research has demonstrated the value of mulch to trees and shrubs. Properly applied mulch under young trees has been shown to increase the root densities underneath the mulch by four times over unmulched trees. Under mature tree canopies, proper mulching has increased fine root densities by 15 times over fine root densities of trees growing with turfgrass competition. Curiously, once a person has decided to mulch, the problem is often one of over mulching. The problem can be called, "Too much of a good thing." We have all driven by commercial shop- ping malls where the landscape crews have cre- ated mulch volcanoes at the base of the trees in the parking lot. Mulch is mounded six inches, 12 inches or even higher on the base of the tree trunk. Many people having seen this done over and over again begin to believe that this type of mulch volcano is the proper way to mulch. Not only is over mulching wasteful of expensive mulch, but over mulching and mulch volca- noes can damage the trees the landscape main- tenance company and the property owner are trying to protect. Mulch Ado, continued on page 9 Volume 5, Number 4 for this tree. Florida Arborist Winter 2002 Mulch Ado, continued from page 1 Tree bark and above ground stem tissue is very different from root tissue. These above ground parts must be able to dry out and respire (breathe) and cannot withstand a constantly moist environment created by the mulch against the trunk. Unlike tissue found in roots, the inner bark tissue in the aboveground trunk can become damaged underneath mulch. This vascular tissue is used for translocation of water, nutrients and carbo- hydrates between the roots and the canopy. Covering the base of the trunk with mulch or soil will cause this type of damage. Even letting a sprinkler head constantly wet the trunk during irrigation cycles could cause problems with the trunk tissue. You should be sure your trees have the root flare exposed. The root flare is the lower portion of the tree trunk that widens (flares out) at the surface of the soil. Covering the root flare can create problems just as covering the trunk above the Haze. If you have a tree where no root flare or buttress roots are visible, that tree is probably planted too deep or has mulch or soil piled over the root flare. A good rule of thumb is to be sure mulch is pulled back from the stems and trunks of young trees and shrubs by at least three to six inches. For mature trees, mulch should be pulled back from the root flare, which is at the base of the tree from eight to 12 inches. For new transplants, we recommend pull- ing mulch back to the edge of the new rootball to allow for better water penetration into the rootball during those critical weeks during establishment. So now you are not going to pile the mulch against the trunk, but how deep should the mulch be? On well-drained sandy soils, try to maintain a mulch depth of three to four inches. With course-textured mulches such as pine bark, more mulch can be applied because oxygen can easily penetrate through the mulch to the soil and the roots. When mulching poorly drained soils, a tvyo-inch layer of mulch is sufficient. Examples of areas of poorly drained soils are low, constantly wet areas in your yard or lots next to canals where fine textured canal dredg- ing material has been used as fill dirt. A fine-textured mulch can hold more water and create drain- age problems more than the same amount of course-textured mulch. If you can only apply one or two inches of mulch be- cause of drainage problems, you may not have enough mulch to provide adequate weed control. If that is the case, the use of an appropriate herbicide may be helpful. Check with your local extension office and read and follow the herbicide label carefully before applying herbicides to mulched areas near trees and other valuable plants. Deep mulch can make moisture problems worse. Before you apply mulch over previously mulched areas, rake and probe the existing mulch to verify how deep the mulch is and to break up any hydrophobic layers that may prevent water pen- etration through the mulch. Adding fresh grass clippings, leaves or too much green plant material to the mulch layer can cause hydrophobic layers to form in mulch. This hydrophobic layer can become colonized with fungi and dry out. This layer will then repel water and keep rain and irrigation from penetrating the mulch into the soil. If you do have a problem with hydrophobic mulch, mix the layers of mulch with a rake or pitchfork. You may find that you disturb roots that have grown into the mulch so work care- fully to avoid cutting or breaking to many roots. Remember too that over mulching will not give an immediate, dramatic sign of a problem with your tree. Much like construc- tion damage to tree roots, over mulching can start a slow de- cline that only becomes appazent after one to five years. And by the time a problem is observed, it could be too late to take corrective actionbecause of decay damage to roots and vascu- lar tissue. Another question is how wide should I mulch? If you look at a mature tree, that tree is constantly and naturally self-mulching by dropping leaves and twigs beneath and slightly beyond its own canopy. It may not be practical in your landscape to mulch every tree out to its dripline; but try to mulch as far out from the trunk as you can. On oval shaped trees roots grow out from the tree about as far from the trunk as the tree is tall. On spread- ing tees, roots are way beyond the dripline. The wider the mulched area, the better are the growing conditions for the tree and its roots. There is also one caution about using mulch. Do not mulch with lawn clippings (fresh or dry) from turf that has been treated with an herbicide unless you are sure the herbicide residue will not adversely affect the plants located near where you are ap- plyingthe mulch. Also, avoid sour-smelling mulches, those that smell like ammonia or urine. These sour mulches have not been adequately aerated or composted and may contain some natu- rally occurring chemical toxins that can damage plants. Fur- ther composting with adequate moisture and stirring for aera- tion is recommended. Finally, another problem with deep mulch and mulch volca- noes is gnawing rodents. Rats and mice can find the deep mulch a perfect habitat while they chew on the cambium and phloem tissue and girdle the tree. That alone is a good reason to keep mulch back from the trunk. In conclusion, remember to mulch as wide as possible but not too deep. And keep mulch back from the trunk of the tree or shrub. Editors note: Ongoing research at the University of Florida is be- ginning to show that mulch applied over the root ball of recently planted trees can actually INCREASE stress after planting. A fu- ture article will explain this in more detail ~ 9