Wooly in the spring time.

In the spring of 2004, one of my many duties was driving around south-eastern Pennsylvania spraying hemlocks for woolly adelgid. As PA passed through my rear view mirror in winter of 2007, I was relieved in the thought I'd never have to spray a tree or shrub again.

Fast forward to the spring of 2011. I'm in my first season as PHC Manager of Heartwood Tree Service in Charlotte North Carolina, and once again I find myself treating hemlocks for woolly adelgid.  Generally speaking, the greater Charlotte area isn't the best habitat for eastern hemlock.  Poorly-drained clay soils combined with the intense Southern summer heat is in contrast to the well-drained organic soil and cooler weather hemlocks are found inhabiting in the wild. 

This specific site was just outside the city limits, on the Eastern side of what barely passes for a mountain.  It was a prefect micro-climate, with blooming mountain laurels lending feel of being in the Appalachians.  As I ascended the hill past the gated entrance, a small grove of semi-mature hemlocks appeared before me.  The trees bore the all too familiar white fluffy signs of woolly adelgid nestled at the base of the needles.

There are many options for control of woolly adelgid.  Because of the number of trees and amount of area that needed to be treated, horticultural oil seemed the best option.  Horticultural oil is gentler on beneficial arthropods, and breaks down fast in the environment.  Soil or trunk applied systemics would've been time consuming and costly to apply.  The brand of hort oil used was also OMRI certified.

Two seasons of treatment, and almost 100% control had been reached.  Sometimes the simplest, and cheapest, treatment is the best course of action.  Though something to consider, pest pressure is low on this site

Treated hemlock with no adelgid.

Untreated with adult insects and nymphs creating woolly covering.

Protect the Zone

There are many standards for tree protection zones.  Some simply state extend a zone of protection to the dripline.  While others are more specific, stating 1ft to 1.5ft for each inch of DBH away from the trunk.  These standards are guidelines.  Tree species, size, age, perceived condition, and vigor all play a role in setting up a final tree protection zone.  Younger trees (species dependent) can probably stand a little less protected soil space compared to a mature tree.

We also need to get away from the thought of a 'tree protection zone,' and start considering a soil protection zone.  After all, its the soil the tree lives in post-construction that will determine overall health in most situations.  If we can't get the desired radius from the trunk on one side of the tree, then consider extending the radius of protection zone further on another side of the tree.  Don't think in minimums, think in maximums.  What is the maximum amount of soil I can protect around this tree?  Numerous studies show that soil volume has a direct effect on tree health and size.

Below are some pictures from a tree and soil protection zone we installed a few weeks ago.  In this case, an addition was being added to an existing home.  We were limited by what area to protect by where the addition was extending, the road, and a driveway.  In this case root pruning was in order to make clean cuts vs. the ripping that would occur when an excavator found the root.

The site and tree (Carya illinoinensis)

A trench was dug using an Airknife to expose roots that may interfere with construction. 

Example of a clean cut root.

The final tree protection fencing. We plan on creating signs to hang on all sides of the protection zone explaining what it is and why it's there.

I smell something ferty.

Something often forgotten is that our NPK fertilizers and recommendations are based mainly on agriculture.  Most often farmers plant multiple acres of the same crop.  The crop grows from seed to maturity in these fields, absorbing all the elements essential for plant growth from the soils.  When the crop is ready for harvest the entire plant is removed from the site leaving bare soil.  Even when fields are rotated this process happens often enough to burden the soil.  In these situations, complete fertilizers with high NPKs are necessary to replace elements robbed from the soil when plants are taken from the site.

Landscape trees and soils are managed in completely different ways.  While top soils are usually stripped and vegetation removed during the construction process, it's usually a one time event.  Most soils are still able to retain many of the elements essential for plant growth.  Trees, shrubs, and other plants also produce exudates.  Though still not fully understood, exudates promote soil micro-organisms which produce available soil nutrients over time. 

Many studies comparing fertilizers and methods of fertilization often show trees respond best to simple correct mulch applications.  Trees have evolved in forests where leaves, branches and trunks are left to decay.  Correct mulch applications mimic this dynamic.

If you suspect nutrient deficiency in a tree you're managing, it's important to identify which nutrients are lacking.  Misapplication of the wrong fertilizer can be a waste of time and money, and may hurt the tree further if one element is raised to damaging levels.

Typical Soil Analysis 

Tree myths, that's what's up.

This past week I saw an article from The Guardian about tree myths posted by The Garden Professors BLOG: http://www.guardian.co.uk/lifeandstyle/2013/apr/28/nine-gardening-myths-debunked?INTCMP=SRCH  I know what you're thinking, some one else spends spare time writing about plants.  But for-real, it was pretty interesting, and I'd encourage you to give it a read.  Below are my comments on the 9 myths they choose.

MYTH 1 Compost tea suppresses disease:
Compost tea can be a polarizing topic for arborists.  Compost teas are a way to introduce organic matter into the soil.  Over time this can improve soil nutrient availability, texture, and structure.  Compost tea pushers have made many claims, including that foliar application of compost teas can prevent leaf diseases.  That's just silly.  Wetting leaves with seeped organic matter may actually encourage the development of leaf diseases.  Most leaf spot fungus require a cool wet environment to proliferate, and spraying leaves with compost teas may provide the moisture.

MYTH 2 Lighten clay by adding sand:
I've seen arborists attempt to drill holes in clay soils and back fill the holes with sand, or a large aggregate like stalite.   The problem with this strategy is it ignores a basic principle of water.  Water does not move in between different textures well (i.e. course texture aggregate to a fine texture clay).  So when this management strategy is employed there is still poorly drained clay with sand filled holes full of water.

MYTH 3 Young trees should be staked:
Trees need to move naturally in the wind to put on reaction wood and build taper.

 MYTH 4 Sun through water burns leaves:
 This seems commonly reported on Japanese maples. In most cases it's actually fungal leaf spot, which really is just an aesthetic issue.

 MYTH 5 Tree wounds need dressing:
Most decay fungi need moisture to survive. Painting an open wound can allow moisture to build up behind the sealant, thus creating a perfect habitat for fungi. Now there have been some studies that show some wound sealants may discourage some insect pests from invading new tree wounds.

 MYTH 6 Biodynamic is best:
Using astrology to pick days to plant?  I suppose it would make sense to some early 20th century gardeners. 

MYTH 7 Gravel helps containers drain better:
Once again, water does not like to move between different textures. Putting gravel at the bottom of a pot has the exact opposite effect, keeping water in the finer texture soil longer.

 MYTH 8 Add bone meal and compost when planting trees:
Digging a tree, transporting it to a new area, and then planting it in a foreign soil is a big stress to a plant.  Throwing it in to a super nutrient rich media, believe it or not, can traumatize a new transplant.  Caution needs to be taken when choosing what type of amendments are being put in to the soil.  As the article states, adding to much of an element, like phosphorus, can inhibit plant growth.  More may often not be better, especially in the landscape.

MYTH 9 Natural is safer:
There is no such thing as a safe poison.  Be it found in nature or man made, poison is poison.  We use pesticides to kill pests and diseases.  Some are less toxic than others, and some have different modes of action.  When choosing a pesticide the mode of action, its persistence in the environment, etc. should be your deciding factors.  Not that it has an OMRI stamp and is made from dandelions.

'Tis the season

The approach of spring means the beginning of 'spray season' for many tree companies.  Any time we introduce a product into the environment, pesticide or fertilizer, we are altering the ecosystem.  It's important to consider some things when choosing pesticides.  How the active ingredient controls the pest and it's residual in the landscape are important concepts in an integrated pest management program.  Care should be taken to choose products that do the least amount of harm to beneficial/benign arthropods.

Pyrethrin and spinoside are two chemicals that control many of the same insect pests.  Both mimic substances found in nature.  The difference? Pyrethrin is an indiscriminate killer of most insects and arachnids, including beneficial insects like lady bugs and mantises.  Meanwhile, spinoside has a low toxicity to many beneficial insects plants rely on for protection from herbivorous pests.  Part of integrated pest management practices are preserving, or restoring, the natural balance between pest & prey in the landscape.

Lady bug feeding on a canker work.

Another thing to keep in mind; organic is not a synonym for safe!  There are Organic Materials Review Institute-approved pyrethins that will kill most all arthropods that are exposed to the product.  Meanwhile, there are completely man-made synthetic products that will effectively control the target pest, while preserving beneficial insects.  When developing a pest management strategy, it is imperative to research active ingredients, modes of action, and persistence in the environment.  Read the labels.  Ask questions of the product developers and your local extension.  Those people are great resources, and are there to help.

Climb on Climber

This weekend (April 13th-14th 2013) was the annual Charlotte Arborists Association Tree Climbing Competition.  It is one of the few open invitational tree climbing comps out there.  Climbers and volunteers from all over the world meet in the quaint "New South" City of Charlotte, NC for 2 days of peer learning, camaraderie, climbing, and fun.

Tree climbing competitions are a great place to learn new techniques, meet new people, and make great friends.  I've volunteered at TCCs from Pennsylvania to Louisiana, but there is one thing about comps that has always bothered me.  We can really torture some trees during these events.  Starting with set up day, the interior of the work climb tree and a portion of the aerial rescue tree is often over thinned and lions tailed.  Then on the day of the event, competitors run through the preliminaries as speedily as possible, jerking branches, smashing bark, and pulling on limbs with full force and weight.  It's like creating an artificial storm the trees must endure, with over pruning resembling the resulting loss in photosynthetic area.  We also invite spectators to mass around these trees, thus leading to potential soil compaction around, most often, mature trees.

Water oak once used as a work climb tree.  Notice numerous small pruning wounds throughout the interior of the crown.

A friend of mine once wondered if any data had been collected comparing tree health/vigor as pre and then post work climb tree.  His feeling, based upon past competition trees in Charlotte, is over all heath of the tree may decline after the event for reasons stated above.  Now this could be coincidental, or it may be that competition trees in Charlotte are used in consecutive years for different events.  If the health of these trees are being affected by repeated use, this may be a lesson to other competition organizers. It may be best practice to be one and done with trees chosen for competition.  Trees create reaction wood and adapt to their environment over time.  The sudden assault of a tree climbing competition could potentially be quite a stress for a tree.

I love tree climbing competitions, and by no means I am I suggesting they be abolished.  We are arborists, and our job is to care for trees.  This basic principle of our job shouldn't be forgotten for the sake of competition.  This year in Charlotte our head judge was Chip Hildreth, and he is a firm believer in this idea.  Chip asked the trees be thinned as little as possible for work climb and aerial rescue.  While, I don't remember his exact quote, his sentiment in the competitors meeting was similar. We are arborists, and our job is to care for trees.  Damaging the tree during the competition would result in harsh judgment and points deduction.

Our techniques and tools, along with our understanding of tree physiology are improving on a daily basis.  Our approach to tree climbing competitions, both their set up and execution, with regard to tree preservation will also improve.  One of Chip's ideas is to change the way some events (i.e. work climb) is scored.  By taking the time component out of an event like work climb, and concentrating solely on scoring by technique and finesse, we may be able to save some wear and tear on the tree. 

2013 Charlotte TCC work climb tree.  Notice preserved small diameter interior growth.  This picture was taken after the event was competed.

But enough of my ramblings, here are the final results from the 2013 Charlotte Arborists Association Annual Tree Climbing Competition (Do not hold me to the spelling competitors names):

Apprentice
3rd Jordan Lopshire
2nd Celestino Flores
1st Adam Hawthorn

Journeymen
5th Noel Boyer
4th Chris Bramlage
3rd Derek Martin
2nd Kevin Bingham
1st Cormac Nagan

Women
2nd Sage Way
1st Marilou Dussault

I'm fixin' to fix some nitrogen.

We know that plants in the legume family (i.e. black locust & soybeans) covert atmospheric nitrogen into a form that is available for root absorption in the soil. However it's not the plant fixing nitrogen, but bacteria known as rhizobia that form a symbiotic host relationship with the plant doing the work.

The nitrogen cycle borrowed from: http://kamuspengetahuan.blogspot.com/2011/08/daur-siklus-nitrogen.html

Similar in away to mycorrizal fungi, the plant provides sugars to the bacteria, and in return gains benefits from increased uptake of nitrogen. This relationship is only formed on sites that are deficient in available nitrogen. Root hairs are prompted to grow around the bacteria forming characteristic nodules.

But wait, there's more. Less thought about Frankia, a species of actinobacteria, form the same symbiotic relationship with 24 genera of actinorhizal plants.  Trees in this group are varied, and include Alnus (sample species: red alder), Myrica (sample species: wax myrtle), and the often loathed Eleagnus (sample species: autumn olive).  This plant bacteria relationship is a major source of nitrogen fixation world wide, and many if these species are commonly found in our landscapes.

Root Nodules

To see a list of actinorhizal plants check out this site: http://web.uconn.edu/mcbstaff/benson/Frankia/PlantBiology.htm .  If you find these guys, do some digging around, and see if you can find the unmistakable nodules.  Because the list of actinorhizal plants is quite varied, and includes several species of ornamentals, incorporating these plants in to our landscape plans can be a natural and sustainable why to get available nitrogen into our soils.