Portland Oregon Landscape and Tree Care

Tree Care and Preservation Tips

Text Copyright 2003 - 2009 by Mario D. Vaden

Miscellaneous tips for tree care, randomly written off-the-cuff

Too often, tree care and pruning knowledge are underestimated. The work of many landscape designers, landscape architects, landscape contractors and yard service technicians, depends on arboriculture knowledge. Even homeowners need tree care knowledge, because proper tree remains the same whether it's done by a professional or by an amateur. If we care for trees right and space them properly, our workmanship will remain as a legacy.

Root Tunneling can may be better than cutting.Tunneling under roots is often much better than cutting through them.

If shrubs or trees fail to have a pruning remedy for where they are planted, they cannot remain as attractive ornamental specimens - not without loosing natural characteristics. A landscaping professional must master an understanding of pruning to effectively master landscape design and maintenance. This is why average homeowners usually achieve no better than beginner status without pro help. Whatever you call it - tree care, arbor care, arboriculture - its not a matter of being certified as an arborist or a landscape technician; its a matter knowing right from wrong, and being able to 'read' a complete landscape picture.

Fertilize trees only when needed. Healthier, or faster growing trees may have larger leaves and needles, but larger leaves are a characteristic that equates to environmental damage. Large leaves provide more surface for wind to tug at and snow to accumulate on. In my opinion, trees need enough fertilizer to eradicate signs of nutrient deficiency, by not enough for vigorous growth. Aim for moderate growth rates. When you read various books and websites, it's reletively indisputable that certain nutrients will boost certain plant functions. But some nutrients will alter natural growth characteristics and form so significantly, that routine fertilizing will be undesireable. Fertilize trees for a specific reason. Unless you are a nursery growing trees for money, speedy growth should not be a reason.

Soil compaction may be one of the few reasons for deep root feeding - maybe better phrased as "deep root injection" since injection can deliver beneficial microorganisms instead of fertilizer. As soil is penetrated for this kind of fertilizing injection equipment,, layers of compaction can be loosened where the equipment enters soil. This disruption of compact soil may prove more beneficial than the deposit of the fertilizer. This can be a good opportunity to add beneficial microorganisms to the ground, and those include mycorrhizal fungi, which is explained more on the tree feeding advice page.

Fertilizing trees can be as simple or complicated as you want. Ideally, you want to add only what the tree needs. You can check for a local extension service that may do soil tests, or look for a garden center that sells test kits. A soil test will be one of the best ways to know how much to add of various nutrients.

At least in Washington and Multnomah Counties of Oregon, soils tend to have enough micronutrients to get by. The macronutrients like Nitrogen, Phosphorus and Postassium will be the ones applied the most. The Phosphorus and Potassium don’t move in the soil very much, so those may be good candidates for inserting in soil through small holes - a pro may inject or bore a hole, a homeowner could use a small auger shaped drill bit.

The internet is a great tool for locating information on fertilizing. Enter search terms like "tree" and "fertilizing" and "university" and "extension service." Many of the higher education research sites are well constructed. Take that recent information and apply it in moderation. Feel free to revisit these resources in case information changes or develops. Different university websites have information targeted for that region.

Avoid parking vehicles over the root system of trees, especially when the soil is wet. This can cause soil compaction, later interfering with the movement of air and water, to and from the roots. Similar problems can occur where livestock compact soil by walking around trees. Even dogs can be heavy enough to cause this kind of soil damage given time.

One pre-existing type of compaction that may exist - and its "sneaky" sometimes - are tillage pans. These can date back from dacades ago. When farm implements, like the old plow discs, were used, the implement would - or could - cause a layer of compaction at the lowest depth it reached. Sometimes these layers cause problems for roots and drainage when the land is converted into a landscaped property later on.

If your area gets snow or ice in the fall, avoid planting trees that loose leaves late in the season. One beautiful tree that fits that group is the Sweet Gum - Liquidambar styraciflua. It is weak to begin with. And has ridges on bark of limbs, increasing the surface area that ice can cling to. And the final death blow to this Liquidambar is late shedding of leaves. Adding that to weak wood invites significant destruction or disfiguration. If you have a Sweet Gum already, consider yearly pruning.

Keeping a mulch under trees can be beneficial even if the mulch is the leaves or needles from the same tree. Mulch receives the first impact of rain drops before they hit the soil. Since raindrops can cause compaction by impacting bare soil, it will be helpful to maintain a layer of needles, barkdust or compost.

Also, mulch decomposes, supplying nutrients to the soil, and adding natural chemical compounds that help soil become, or stay porous. Keeping a mulch on soil is one step closer to a forest environment where there is a decomposing layer on the soil from leaves that fall and remain.

Proper pruning cutTo protect the branch collar, a pruning cut should leave an appearance similar to this. Not a stub - not a flush-cut.

Avoid planting trees in large quantities, known to have problems or pests associated with them. Take Shore Pine - Pinus contorta - for example. In western Oregon, that tree often gets damaged by the larvae of Pine Pitch Moth which chew here-and-there under the bark, causing weakness on the trunk and branches. A tree like Shore Pine, may best be planted singly, or up to three, but certainly not in groups of nine or eleven - primarily if it's going to dominate the tree planting on the property. As the landscaped area increases, the groups of susceptible trees can increase a bit too.. In the same boat would be Sweet Gum for weakness and several Flowering Cherry for disease. Maybe Japanese naple too. Read about each tree, and see if there are significant associated problems. Flowering plum can be weak and Leyland cypress can get a canker or become too enormous.

If you stake newly planted trees, put notes on your calendar to check the ties wrapped around the trunk, for no later than 1 year after staking. In most cases, healthy trees that were planted properly will not need stakes after 1 year.

When establishing trees for the first few years, be sure to keep mulch over the root system to retain moisture until the roots can grow deeper into the earth. After a few years, keep mulch under trees to prevent compaction from rain drop impact.

Consider reducing or eliminating irrigation from established trees, except when extended dry periods prevail. Irrigation promotes surface rooting, and trees need deep roots to remain anchored during wind storms, not surface roots that peel loose and allow trees to topple. This can be especially important for tall trees like conifers which reach above 50 or 100 feet. They retain foliage in winter, and that's more that the wind can push against. In natural forest environments of the United States, a lot of conifers don't receive much rain during the summer time.

Some trees will benefit from routine watering. Use a good garden or tree care book to research the watering needs for your tree. If regular watering is not an essential "need", my preference is to lean a bit more toward the dryer side, than the wet side.

Adhere to about a 20% canopy removal rule for pruning away limbs or foliage. If your tree has many undesireable, damaged or rubbing limbs, there is no need to remove them all in one year, unless they were all life-threatening, which usually is not the case. If removal of every undesireable limb will exceed 20% removal of the canopy (or maybe 30%), consider spreading out the removals over 1, 2 or even 3 years.

Sometimes you will not want to remove limbs or excess trunks that rub other ones. In some cases, removal of limbs or trunks like that, disfigures the tree so significantly that its better to leave them alone and do the best you can with the rest of the tree. Often it adds character more than it adds an eye-sore. Sometimes, limbs will rub or press against one another and 'bond' or graft together. You may have no choice but to leave some them.

In general terms, the question 'When should a tree be pruned”, can be answered easier by describing first, what time of year a certain type of pruning should be avoided. The bad combination of pruning and time, are topping and late spring to summer. If you were to prune the top off of an apple tree (or 'top” a hedge like Photinia) in mid-May, or June, don’t be surprised if the top bark of your plant gets 'barbequed” by sunlight. Its not unheard of to get 90 degree weather in May. If you prune too late, and new growth does not yet cover and protect the top bark, sunlight can severely burn the exposed bark and tissue, rendering permanent damage. Do your heavy-duty top removal pruning before the middle of April. Other than that, consider the entire year as a safe season for moderate corrective pruning and thinning of trees and shrubs (meaning within the canopy).

If you remove trees for development, or whatever reason, check to see if the removal drastically increased direct sunlight to the trunks of other trees that were previously shaded. If a situation of increased exposure occurs, wrap the newly exposed trunks for a period of at least 1 year until an adjustment to the extra light has progressed. My preference would be a window screen or shade cloth screen material as opposed to a solid white wrap. White reflects light, and if the material is too solid, it may reflect too much light and allow too little to pass in to the bark tissue area. A screen like shade cloth blocks some light, but also allows some in. The idea is to allow the bark to adjust and make a transformation, not to block all the light. Don’t use material that has little or no porosity. Trunks need air circulation. That’s because trunks 'breath', and its beneficial for bark to dry and not remain moist for excessive periods of time.

protect tree trunkTree trunks should be protected from summer sun when planted after winter. Staking - if used at all - should be very temporary. Mulch in important to retain moisture, reduce soil compaction and prevent water runoff.

Leaves can be beneficial as organic compost when left under most trees. But at least one exception is leaving Apple leaves under Apple trees. Its more of a disease issue than a nutrient issue. Apple leaves will provide nutients. On the other hand, Apple leaves work against benefits of sanitation in the fight against disease such as fungus. Remove Apple leaves from under Apple trees. This provides a sanitary environment, and allows overspray from dormant season application spraying to 'rain' down and 'neutralize' fungus spores remaining at the soil surface.

Remove apples (the fruit) laying on the ground. Apple fruit emits a vapor, or gas, that will accelerate the ripening of fruit on Apple trees. Removing that fruit from the ground will also provide a less hospitable visitor center for Yellow Jackets that swarm around fallen apples. It may be beneficial for you to put an apple in a bowl, or container with other fruit. The vapor emitted by apples can be beneficial when you need to hasten ripening other fruit.

More about Yellow Jackets - these tend to lurk in the vicinity of trees that have tiny insects like Aphids. In almost all cases where we have seen Yellow Jackets swarming around the canopy of a tree, there were insects, or, a hive. If you see Yellow Jackets swarming around your tree, be alert. First look for a hive. Check for a concentrated flying population that may indicate the entrance and exit from the canopy, to and from a hive. If you look for Aphids first, and disturb a hive that you were not looking for, you may regret the search priority. First check for a hive. Next is the search for tiny insects.

tree root barrier panelTree root barrier panels may allow you to plant trees closer to septic fields. The root barriers also can protect pipes, sidewalks, water meters, driveways and foundations.

In the west portion of Oregon, not every conifer will be an object of concern for Spider Mite attack. At least near Portland, its typical for trees like Douglas Fir or Ponderosa Pine to thrive without a Spider Mite siege. Even if those were targeted by Mites, treatment would exceed the budget of the average homeowner considering the massive size of these trees. Arborivitae is a likely target, and Alberta Spruce is another small evergreen frequently attacked. Check these and other host trees for Spider Mites, about every 3 weeks during warm or hot weather, especially when temperatures soar. If the Mites are too small to spot, hold white paper under a branch, tap the foliage, and look for 'moving dust' - Spider Mites. Spider Mites are not an insect, so many insecticides are innefective. You want a spray that kills Spider Mites. Some pesticides are labeled to 'control' these Mites. Control is not the goal, eradication is. You will need a spray specifically labeled for eliminating these Spider Mite pests.

If there are tree roots headed for your driveway or sidewalk, consider cutting them now while they are small. Trees will grow best if no roots are damaged or cut. But people with common sense can put 2 + 2 together - if the root lifts the concrete, that root will probably be cut anyway to replace a new sidewalk at the proper grade. But by leaving root pruning until later, after concrete damage, the diameter of the cut will be larger in diameter. Why wait for damage and a larger cut? Make the cut now while the root is small, and before the concrete gets cracked. Its easier on the tree. Easier on your savings.

Several people like the limbs and canopy of their evergreen trees to reach the ground. If this includes you, at least prune off branches that drag on the ground so branch bark does not root into the soil. That can present difficulties later. Ideally, there should be enough space under the limbs to rake out excess dead needles. If too much dead debris builds up, directly under foliage, then fireworks and other sources of ignition can start a fire which may totally destroy the tree. Why not spare 12" of branches to preserve an entire tree?

broken tree branchThis tree is not salvageable anymore. All that was needed to prevent this damage, was removal of a tiny branch / leader at planting time. It would have been a small cut, like 1" in diameter.

Pesticides, like lawn herbicides, can be detrimental to trees. Now and then, a tree will start to die in a yard - a tree centered in the flow of water run-off from a lawn. In some cases, its not just the excess water that kills that tree (although that’s possible too), but herbicides carried from the lawn to the tree during heavy rain or excess irrigation. This is why spot treatment for weed spraying may be better than treating an entire lawn. A good design strategy for avoiding this nature of poisoning, is placing trees above-grade from depressions where run-off will flow. If you already have a tree in a low-spot similar to this, consider a small french drain to catch water uphill from the tree, and route the water around the tree, bypassing it.

If twine (that holds burlap and a root ball) is not removed during planting, a tree can be 'girdled.' The twine can become enveloped by the trunk as the tree grows. For this reason, twine should be removed when the tree is planted. This is so critical, that its worth the investment of time to double-check every tree, even if they were planted by a professional landscaper or arborist. There are cases where residual twine is double. That’s when burlap and twine, are wrapped around a tree root ball that also has other unnoticed twine wrapped around the trunk. Sometimes a professional will remove the twine, not realizing that there is a second set of wrapped twine. Each tree should be inspected during planting to make sure that the twine is cut loose, AND, inspected more closely to make sure that another wrap of twine is not present.

Sometimes, barkdust, or similar mulch, packs down, and becomes a thatch-like hard crusted layer. If you have barkdust in this condition around your trees, make an attempt to loosen the layer. Its usually not difficult. Without damaging surface roots, use a cultivating tool, a miniature rototiller, hoe, garden fork or other device, to fluff and disintegrate the hardened layer of mulch. Then rake it smooth again.

Pointing to where the branch meets the branch collar at the trunk. Avoid cutting into the branch collar when pruning.

Some companies can inject insecticides or fungicides into trees. This may be an option for people that do not want over-spray floating around the air in their yard. This injection is a systemic approach for eradicating bugs and tree germs.

Systemic insecticides - read the label carefully. Be sure that you do not apply systemic insecticides near the root systems of plants that provide food for humans and animals. Systemic insecticides enter the tree through the roots, finally moving up through the trunk into stems, leaves, fruit.

If you ever transplant a tree, whether by hand, or with a truck mounted tree spade, be sure to keep the tree oriented the same in relation to compass direction - the same as it was before moving. That means the branches that were facing north, will still face north again. The branches that faced south, likewise will face south again. This strategy is primarily for trees that were exposed to light on all sides - that were growing out in the open.

When you dig a hole for planting a tree, its best not to dig a hole deeper than the height of the root ball. In fact, it may be better for the depth of the hole to be an inch or so less than the height of the root ball. If a hole is dug deeper than the height of the root ball, the trees roots could settle below soil grade if the backfilled soil settled.

Leaving dead branches in trees can accelerate the defoliation of lower, desireable branches. If you prune dead limbs away, this allows more light to penetrate to older leaves or needles located closer in on the branches.

Here is an interesting illustration for the purpose of explaining how trees get fall color. The most simple way to explain it is to say that much of the fall leaf color was already there in the summer, masked by the green chlorophyll. This cropped image is from a US Forest Service source. You can enjoy the wealth of information and publications of the Forest Service online. There are many of them at this link. A wealth of information and research, with illustrations, photos and diagrams. Professional arborists rely on these reliable resources too.

tree care advice

A GREEN leaf is GREEN because of pigments known as chlorophylls . When they are abundant in the leafs cells during the growing season, the green color dominates and masks out colors of other pigments that may be present in the leaf. Thus, leaves of summer are characteristically green. The chlorophylls capture some of the sun's energy and utilize it in the manufacture food - simple sugars produced from water and carbon dioxide. These are the basis of the plant's nourishment - the source of carbohydrates needed for development. In that process, chlorophylls break down and are continually used-up.

During the growing season, the plant replenishes chlorophyll so that the supply remain high; and leaves stay green. As autumn approaches, certain influences inside and outside the plant cause chlorophylls to be replaced at a slower rate than they are being used. During this period, with the total supply of chlorophylls dwindling, the "masking" effect slowly fades away. Then other pigments that have been present in the cells too, all during the leaf's life, begin to show. These are carotenoids; providing colors of yellow, brown, orange, and many hues between.

The reds, purples and their blended combinations come from another group of pigments in the cells called anthocyanins . These pigments are not present in the leaf throughout the growing season as are the carotenoids. They develop in late summer in the sap of the cells of the leaf, and this is the result of complex interactions of many influences - both inside-and outside the plant.In the fall, phosphate, along with the other chemicals and nutrients, moves out of the leaf into the stem of the plant. When this happens, a sugar breakdown process changes, leading to the production of anthaocyanin pigments. The brighter the light is during this period, the greater the production of anthocyanins and the more brilliant the resulting color display. When the days of autumn are bright and cool, and the nights are chilly but not freezing, the brightest colorations usually develop.

Anthocyanins temporarily color the edges of some of the very young leaves as they unfold from the buds in early spring. They also give the familiar color to such common fruits as cranberries, red apples, blueberries, cherries, strawberries, and plums.In our autumn forests they show up vividly in the maples, oaks, sourwood, sweetgum and dogwood. These same pigments often combine with carotenoid colors to give deep orange, red and bronze.The carotenoids occur, along with the chlorophyll pigments, in tiny structures called palstids within cells of leaves. Sometimes they are in such abundance in the leaf that they give a plant a yellow-green color, even during the summer. But usually we become aware of their presence for the first time in autumn, when leaves begin to lose chlorophyll.

Carotenoids are common in many living things, giving color to carrots, corn and daffodils, as well as egg yolk, rutabagas, buttercups and bananas. Their brilliant yellows and oranges tint the leaves of such hardwood species as hickory, ash, maple, poplar, aspen, birch, cherry, sycamore, cottonwood, sassafras and alder. If you found this last bit of information about fall color to be useful, they you will appreciate visiting the forest service web page for many publications. That was my source for this last section.

Tree roots headed for concrete - Some arborists will tell you not to cut tree roots. Some will say its okay to root prune. Actually it may not matter. If the roots end up lifting the concrete, they will HAVE TO BE cut and severed anyway to make room for the new concrete to be poured. And at this phase, the roots that get cut will be larger than the ones that would have been root pruned a few years earlier.

So if the roots are headed for concrete, don't wait. Just get a hatched, ax, old saw or root cutting tool and sever the root. It costs about $500 to repair about 8' of sidewalk. Why deal with that kind of financial blow?

Ideally, when a tree is near concrete, a small trench should be dug about 8” deep along the walk every 2 to 4 years. Every root in that trench should be removed. This should be repeated on regular intervals as long as the tree remains. The roots will almost always keep regenerating toward the concrete. An option is root barriers that insert in the ground. Try location Tree Tools in Lake Oswego for this product.

Metal in trees / hanging plants and bird feeders - Don't be disturbed about drilling a little hole - 1/16” or 3/8” - into a tree branch or trunk to install a small hook or screw eye.

plant hooks in treesMetal plant hangers can become embeded in tree branches. Either inspect the hangers yearly or use a size that's to large and too wide to become trapped. My preference is to insert threaded eyes and back-them-out by one or two turns per year as the wood expands.

Sure, you can loop around a branch, but many times people forget, and the tree branch gets damaged by embedding the rope or wire within the bark.

Tree trunks or branches will grow over a hook, and the branches will still keep on growing, growing, growing.

Another option is to remove the hook before the branch closes up on it entirely. Then the hook can be reinserted in a new location. This method may leave a few small holes in the tree, but people need to be able to have some fun. Don't get stressed over a few tiny holes. Enjoy your days while you can.

Needle drop - are tree dying - Each season in Oregon provides different kinds of plant growth. Spring brings leaves. Summer bring trunk and branch diameter growth. As branches swell with added diameter in summer, needles on evergreen trees are slowly purged away - mainly the older ones. This is a healthy sign. When interior, older needles start to fall in late summer and fall, don't worry. It would be different if the exterior younger needles were discoloring. Then you could get concerned.

Each tree has what is called a needle persistence. Some trees hold 2 years of needles. Then when summer comes, a third set is produced, triggering the release of needles so that when winter has fully come, it still holds only 2 years worth. Some trees may hold 3 years, others 9. Shrubs like Rhododendrons also drop older leaves from the interior in late summer. Just be glad that its a sign of healthy growth.

Staking wind blown trees - Unless you have substantial landscape experience, consider staking all B&B (burlap) trees.

Very often, trees sold in pots do not need staking. Many nurseries do not even anchor the trees in pots because the roots are holding the soil together.. Often the trees are just in rows standing on their own. If the trunk does not wiggle around much in the root ball (or the pot), skipping the staking process is a definite consideration.

Always stake bare-root trees. But stakes should not be left on much past one season or one year. Tree trunks develop better near the base if they can grown unsupported by stakes or wires. The same applies for transplanted trees, trees in pots and burlapped root-ball trees.

If a storm has blown your tree sideways - especially with water-logged soil - staking may be needed, but do not immediately pull the tree back first unless it was a tiny tree and you can rock the entire root system back into place.

In the 1980's, I had the opportunity to work at nearly six golf courses - many trees. Repeatedly, the greens crews pulled trees back into place with a tractor or by hand, and staked them in place with ropes. After time - months or years - once the bracing rope was removed, the next year's storm almost always took the tree over again. Or even the third year's storm if a mellow winter or two were forgiving until the "big one" came along..

The sturdiest solution has been to leave the tree trunk at an angle, and professionally prune and redirect the top to grow up. That along with thinning of bulk and weight. Yes the trunk will have a lean, but the trees that this was done to did not blow over more, or again. And the new trunk growth grew vertical.

A different version of information related to this topic is on the Tree Feeding advice page. It can provide more knowledge for understanding the "big picture" - soil care is an important aspect of keeping trees in place.

Sometimes, it's possible to raise a tree and stake it by anchoring high on it's trunk and running a cable to a high point in other trees if another large tree or grove is behind it. This can cosmetically hide the anchor and allow long-term presence of hardware if you don't want to have a hole in your greenery.