Arborist Insights

Bronze birch borer related pruning

By | Arborist Insights, Trees | No Comments

Because I am ISA certified, tree-related tasks are automatically given to me by default. And that’s fine. This blog post is about a birch tree which exhibited top dieback. So I was sent in with pole pruners and an extendable Stihl chainsaw to take care of the request.



It’s not super clear but the top leader is dead.


Once I took out all of the dead branches, I pruned the live parts of the tree to give it some sort of shape. Then I hauled out the debris up to the road for later truck pick up. Only later did I realize that my boss expected me to take the whole tree down! Not my style anyway.

Since we suspected the cause of the dieback to be the bronze birch borer (Agrilus anxius) my approach was correct. Pruning out affected limbs is the way to do it. I just couldn’t burn the diseased branches on a strata site surrounded by woods. My only hope is that no adults emerged before the debris was processed with other green waste.

Bronze birch borer

Adult bronze birch borers are half an inch long and have slender dark green bodies with metallic bronze sheen. In summer, females lay their eggs in bark crevices of weak and stressed birches. They prefer sunny, south facing branches.

Larvae hatch 14 days later, enter the bark and feed on sapwood. After one or two years adults emerge by chewing D-shaped holes in the bark.


So let’s review. Bronze birch borers cause treetop dieback, leaf wilting on branches and D-shaped exit holes in the bark

What can we do?

Since the bronze birch borer only picks on weak and stressed birches we should keep our birches in good shape with regular watering, feeding and pruning. Also, put your birches in shadier corners.

One other idea is to plant birch borer resistant river birch (Betula nigra) cultivars.

If you are lucky, you will get some help from natural allies like parasitic non-stinging wasps and woodpeckers.

The birch featured in this blog post is still alive and standing.



After removing all dead branches and pruning others to give the tree some sort of natural shape.


Source: GardenMaking magazine no.30, pp.56 and 58.

When trees and artificial turf are incompatible

By | Arborist Insights, landscape maintenance, Landscaping, Lawn Care | No Comments

My friend who specializes in artificial turf installs told me recently that he was killing it. Great. I was happy for him. He went through his apprenticeship by installing NFL turf and deserves his success.

However, there are some cases where installing artificial turf is a bad idea. Take for example the case below from the United States.



Picture used with permission.


Unhappy owner

The owner was unhappy with his lawn and approached his landscape company about replacing it with artificial turf. His landscaper was worried-correctly!-about removing four inches of turf and not adversely affecting the tree. Then she posted this picture in a Facebook group and asked people for their opinions.

Incidentally, I recommend joining a few Facebook lawn care groups. Many of the groups have thousands of members and interesting things pop us almost daily.

Let’s see

This is an interesting case so let’s see.

A) I presume that the tree shades out the grass when it pushes leaves out. You could prune the tree to allow for more light penetration. Another possibility is top-dressing with a light layer of soil and over-seeding with shade grass mix. Baby the lawn a little bit. Aerate it and fertilize it.

B) To install artificial turf you have to remove the top four inches of soil and install rock. You can read my blog about my friend’s project which shows the steps involved in installing artificial turf.

Since trees rely on surficial roots for water and nutrient collection this step would no doubt affect the tree. I also notice large roots that would make it impossible to install the turf perfectly flat.

And to prepare the rock for turf install, it gets compacted with a machine. We know soil compaction kills trees by limiting air and water uptake by surficial roots. Installing four inches of rock and compacting it all around the tree would have serious consequences for the tree.

C) I understand that most artificial turf models allow water to penetrate but I still think it wouldn’t be the same deal for the tree. Then there is the issue of heat. Natural grass produces oxygen and cools down our properties and cities. It’s the opposite with artificial turf. Once it’s installed it heats up and the soil underneath dies. I think the turf would simply “cook” the tree roots.

D) I believe the tree has to go before artificial turf can be installed. Imagine the full effect from grass cooling and tree shade to open artificial turf which absorbs heat and zero shade. Remember, artificial soccer fields should be watered down to protect the players on hot summer days.

E) Then there is the issue of cost. Artificial turf isn’t cheap but it’s easier to maintain than natural grass. I personally dislike anything artificial in my landscapes. Anything that kills soil is bad in my books.


The owners of this property have to find another solution to their grass problems. Artificial turf install is totally incompatible with the tree in their front yard. They can prune the tree and baby the grass. Or they can remove the tree to make way for artificial turf. Of course, this step loses the many ecosystem services provided free of charge by the tree and leads to soil death. I would personally avoid this second idea at all costs.


Chinese windmill palms on the West Coast

By | Arborist Insights, Species, Trees | No Comments

I love palms! They remind me of tropical locations we all love to visit. So when the August 2017 issue of Arborist News featured an article on palms, I finished it on the same day. It also gave me one credit towards my recertification.

This blog post features a palm we see in the Vancouver area. I learned about Chinese windmill palms (Trachycarpus fortunei) after they got absolutely hammered this past winter at a client’s place. The lady was clearly distressed because the fronds were all beat up and brown. Plus, her palm was situated near her pool and outdoor kitchen. So I did the only thing I could; I pruned off the brown fronds. When my client retreated into her beautiful home, I snapped a photo of the palm tag and made a reminder to myself to check the species online.



This poor palm didn’t make it. All growth originates from the top and clearly, not much is happening there. But perhaps there is hope. See the next picture.



We almost gave up on this palm but look at it now!



This specimen survived the winter nicely.


Winter hardiness

Trachycarpus fortunei is the most tolerant to cold temperatures of all palmate palms. But remember, our last winter in British Columbia was the harshest winter in thirty years. My boss almost lost his juvenile Chinese windmill palm this year. See the second picture above. And it just so happens that my boss and my client both live in an area which held on to snow the longest.

The other complication is that mature Chinese windmill palms handle cold better. Younger specimens are most susceptible.


The Chinese windmill palm is a solitary fan palm with a slender trunk. The key distinguishing feature of this palm is a messy layer of brown fibers that turn gray with age.



Note the messy fibers.


The palmate fronds are up to two feet (0.6m) wide and deeply divided into one inch (2.54cm) wide, stiff segments. The petiole is 1.5 feet (0.5m) long and armed along the base with blunt teeth. Yes, the teeth are blunt but weeding around this palm is still unpleasant.

Mature specimens can reach 25 feet (7.6m) in height. This species is a good selection for small gardens.



All brown fronds should be pruned off.



This is a picture after pruning.


What palms grow in your home area?


References: Arborist News August 2017 volume 26, number 4, pp. 12-21. This is an excellent article. If you are ISA certified you can earn 1 CEU credit.

Help your trees with watering bags

By | Arborist Insights, Reviews, Trees | No Comments

It’s very hot in our July British Columbia landscapes and plants need help. Trees are plants so let’s help them with some supplemental water. One great invention is the Gator watering bag.



A Gator watering bag in action. They work best when they are filled with water. Full marks to this dedicated home owner.



Installation and benefits

You don’t need any tools to install the bag. Just put the bag around your tree and zip it up. Then add water. The slit is located under the label tag. Once, when I was working for the City of Coquitlam, an elderly couple walked by and wondered how we get water into the bags. Just lift the tag.

The Gator website states that new plantings require a refill every 5-7 days. The average watering time is 5-9 hours. And the benefits? No run-off and limited evaporation.

You can use the bags to protect young trees which should limit losses and labour costs associated with tree planting. That said, some young trees still don’t survive. Perhaps they weren’t planted properly or came from inferior nursery stock.

Not so fast

It would be great if this was the end of the story. Bags go around the tree trunk and deliver much needed water boost to thirsty trees. Not so fast. Just last week I visited my favourite blog called the garden professors. It’s a special blog because people try to use good science to answer questions.

One post that appeared on the blog site was about Gator bags. The author noticed two problems:

a) Many watering bags were empty!? Since the bags were designed to deliver water to trees they should be filled with water. Obviously.

b) A bigger problem was unzipping the bags and discovering bark rot. As the full bags press against the tree trunk they create moist and dark environment and, over time, this can lead to bark rot. Rotting bark then invites diseases and pests.

So I did my own survey on a large site we maintain. I found one tree with a moist bark section; some had bugs hiding under the zipper.



All clear. The bark was dry and, alas, so was the bag.



Same as above.


Think of the Gator watering bags as a temporary solution. Install them, fill them up and check on the condition of the bark periodically by unzipping the bag. I hope your trees get through the summer heat without injury.

Field sales call survival

By | Arborist Insights, Pruning | No Comments

Spring. It’s a time of renewal and, as the Tri-City News reminded me recently, it also brings out salesmen. But don’t worry, you don’t have to let them in. And you have thirty days to change your mind if your purchase is over $50. Good to know.

I was thinking about this after I had a salesman visit me in the field. The guy simply drove by my work site and saw my piles of branches. My goal for the day was to thin out Robinia pseudoacacias. So he stopped and searched out the sweaty arborist. Normally, I brush salesmen off but in this case, I was very happy to talk to him. As it turned out, he had lots of ‘toys’ in his truck.

Arborist ‘toys’

Doug pulled out a telescoping pole saw which was awesome. It’s a bit heavy but the telescoping is nice. The hand saws had me drooling. I especially liked the hand saws that attach to your leg for easy access. One day, when budget allows, I will invest in one.

Right now I am happy with my Samurai hand saw I purchased in Japan for about $35. Always get good quality steel. Having a nice, sharp saw is critical. I still remember a seminar I took at the UBC botanical garden years ago. They had an arborist doing a demonstration in a tree and his hand saw was gorgeous. Light reflected off the saw and it made a beautiful sound when it cut through the wood. I wanted one like that ever since.

Later on, the same arborist pointed out that his hard hat is worn to separate himself from landscapers. Aha! I was insulted and too shy to interrupt the demonstration. Hard hats are for safety. There are many professionals like me who are both ISA certified arborists and landscapers. Skilled, total professionals. My focus is on good quality work, not on separating myself from anybody. Remember, be so good so they can’t ignore you!

Sales details

I am very happy to plug a green salesman in a blog post. Always help others succeed. Unfortunately, many companies have go-to dealers so it’s up to the salesman to spin his magic and develop new relationships. Saws get dull and abused. You will need new ones.

Doug Cox of Calmac Saw & Supply can be reached at 604-816-6915 or Please tell him you found him through this blog. Perhaps he can demonstrate his saws for you.



Doug Cox’s beautiful saws. Always use sharp saws when you work.



Katsura tree with too many leaves

By | Arborist Insights, Pruning, Trees | No Comments

“Every year this tree makes too many leaves.” That is a direct quote from the strata owner whose patio looked out on a nice Katsura tree specimen (Cercidiphyllum japonicum). I almost laughed. The tree makes too many leaves every year? Really? I talked to her politely and agreed that some thinning cuts were in order. But too many leaves? That deserved a blog post.

Thinning cuts

On a multi-stemmed tree like this one, thinning cuts are totally fine. Just pick a branch that rubs or crosses with others and remove it. You should be able to create some openings in the crown while still preserving a natural tree look. I didn’t have any trouble with this. It was easy to see crowded spots.

Just remember not to go too crazy. You can always come back next year. I made a few cuts on every tree and assessed it before taking more. And I will assess it again once the trees leaf out.

Too many leaves

This is a joke. Trees know what to do. We can’t tell them how many leaves to produce. What’s the big deal with leaves?

Trees use leaves as factories to make food from sunlight through photosynthesis. This is a free service which produces oxygen for us and removes carbon dioxide from the air. This process also releases water which affects local climate. Without leaves the tree can’t survive.

Once the food is made it is distributed throughout the tree. Upper branches can act as storage sites which is why pruning during drought can starve a tree. Under drought conditions, leaf openings called stomata close to prevent moisture loss. This, in turn, means that carbon dioxide can’t enter therefore food production stops. Then, here comes a landscaper with strata orders to prune trees. As he removes some of the upper branches, he removes food that was stored in them. Boom. Starvation ensues.

Leaves also serve as food for various animals and they act as cover for birds. For example, caterpillars munch on young leaves and are in turn eaten by birds.

Leaves also look great in the fall as they turn color. This katsura tree is no exception.

Too many leaves? Not likely. Let the tree do its thing.


Tree planting with West Coast landscape professional Vas

By | Arborist Insights, Trees | No Comments

I love planting trees and shrubs. The world can always use more trees and shrubs. But don’t dismiss tree planting as easy. It has to be done right. The International Society of Arboriculture (ISA) sells a book called “The science of tree planting.” Case closed.

Our mission today was to plant trees on a wild bank to provide residents with a screen. As the trees mature they should obscure the power station visible in the distance.

We planted two tree species (Acer rubrum and Thuja plicata) and one shrub (Pieris japonica.)


Step 1 At the nursery

Always be nice to the workers at the nursery. You don’t want them loading your precious plants like pigs. My job was to count the plants and anchor them in the back of the truck. The key is to always handle your trees by the root ball not by the stem. Taking liberties with the stems could damage the tree.



I love tree nurseries! You can improve your plant ID skills and off-road in company trucks. Handle your trees with care.


Step 2 Digging

We predetermined our hole locations the day before. The digging was awful because of the wildness of the bank. The bank  was covered with woody debris, ivy and bramble. For this reason I used a tarp for “parking” soil from the hole. I used a shovel to measure the size of the root ball. I also had to adjust for the string and burlap wrapped around the stem. The root flare is actually lower than where the string and burlap meet.



Thuja plicata with wire cage, string and burlap. Watch your back, this required heavy lifting.


Step 3 Placing the tree

Once the hole was ready, we carefully placed the tree in the hole. Remember to handle the trees by the root ball NOT by the stem. Once the placement is correct, it’s time to anchor the tree by backfilling the hole to about half way. Another key is to backfill your planting holes with the same material you dug up and placed on your tarp. Some people are tempted to backfill their holes with beautiful new soil but it doesn’t work. Water finds it much easier to enter your planting hole than the surrounding soil and your hole will become waterlogged. This will turn your new tree into a joystick and it will crash down eventually. Use the original material from your digging.



Cut off string and burlap to the top of the cage. Bend wire edges back or cut them out.



Step 4 Removing string, burlap and wire

Once our tree was anchored in the hole, we cut and removed the string. The top of the wire cage is either cut away or bent back into the hole. The top third of the burlap is also removed. Use scissors or a knife.

Now you’re ready to complete backfilling your hole. Always make sure soil doesn’t go over the root flare. The root flare should be visible. Mounding soil over your stem leads to problems.

Cut all strings on the Thuja plicata stems to free the branches.



Partially backfilled for anchoring; note removed burlap and string, wire bent back and tree root flare located.


Step 5 Final touches

Remove all flagging and name tags. Top dress with aged mulch or soil amender. Also take pictures for your files. Monitor your trees just in case if staking is required. The Acer rubrums are tall and if they move, they will get staked. Just remember to remove the stakes after one season. Leaving them on longer prevents the tree from forming reaction wood.

With April rains expected to continue, no watering was required but it is a consideration if you’re planting during a warm, sunny spell.

Pick up any garbage and do a courtesy blow of your work area.




All done! Note power station in the background.




Two Acer rubrum trees. Note top-dressed tree wells. No staking required but landscape maintenance crews will monitor.


I’m curious to see how many seasons it will take for the trees to obliterate the view of the power station.


Tree well mulch mountains disaster

By | Arborist Insights, landscape maintenance | No Comments

Mulch mountains in tree circles is a disaster that just won’t go away. I had written a short blog post about this in 2015. Fast forward to February 8, 2017. Sitting in on a lecture by Dr. Bruce Fraedrich of Bartlett Tree Experts, I was reminded of this issue again.

According to Dr. Fraedrich, he has been talking about this issue for over 25 years! The issue isn’t going away. In his presentation he showed one tree well mulch mountain with his child; the other photo was with his grandchild. Point made.

Why mulch?

There are many benefits to putting mulch into tree wells. If it’s installed properly. Four key benefits are listed below.

  1. Water conservation.
  2. Weed reduction, assuming we install the mulch at a decent depth. Going light on mulch can actually encourage weeds to grow.
  3. Improved soil quality.
  4. Enhanced plant growth.


The key issue




The installation workers, presumably landscapers, piled the mulch way over the root flare. It looks pretty. But it’s bad for the tree. Why?

Piling mulch against the trunk of trees and shrubs creates a dark, moist, low oxygen environment to which above-ground tissues are not adapted. See the picture below. Fungal diseases require precisely this kind of moist environment to grow and reproduce; and to eventually enter the plant.

Opportunistic pests are also more likely to invade a plant whose bark is wet due to excessive mulching.

It is also possible to get adventitious roots developing in the moist zone. These roots grow and circle the tree potentially causing girdling.





Extend the existing tree circle out farther, if possible. Then remove all excess mulch from the trunk and use it in the extended circle zone. If the circle can not be enlarged then still remove the excess mulch and use it elsewhere.

The look we want is donut-shaped. This will protect  the soil environment and above-ground tissues.

Include this work in your regular landscape maintenance. Periodically check your tree wells and remove any excess mulch from tree trunks. Train all staff.

Coordinate with installers. Sometimes they are young labourers with strict time guidelines. Sometimes companies send people to blow mulch in. They need good directions and supervision.


Winter tree plant ID quiz: advanced edition

By | Arborist Insights, Plant Species Information | No Comments

As I write this blog post, the Lower Mainland is experiencing the harshest winter in thirty years! Last week some of our days were shorter so I used the time to study and to create blog posts. I think this might be a good time to look back at the 2016 season and review some tree names.

This tree ID quiz features lots of seeds and plant parts. It will challenge new landscapers. Do your best. Veterans should be able to ace it. Find the botanical names. Common names are fine but get used to learning botanical names.

Ten questions. Why not challenge your co-workers and friends. Check your answers below. 10 botanical names= 10 points; take 1/2 points if you only know the common name.

Plant identification skills are critical to our success as landscape professionals. Getting to know plants can be hard work but it’s also fun to know what populates your landscapes. Once you know what you have you can maintain it properly. You can also educate your clients and your new co-workers.


































10/10: ask for a raise! You might be ISA or landscape certified

7+: veteran landscaper

5+: not bad!

1-5: review the whole list and ace my next quiz



  1. Liriodendron tulipifera (tulip tree flower parts; the tree flowers AND leafs out at the same time which is why people often miss the flowers)
  2. Liquidambar styraciflua (sweetgum-common landscape tree and beautiful alternative to maples)
  3. Styrax japonica (common landscape tree with beautiful snowbell flowers)
  4. Alnus rubra (native alder)
  5. Robinia pseudoacacia (long seed pods are hard to miss in the fall)
  6. Quercus robur (English oak, nice change from pin oaks Quercus palustris)
  7. Carpinus betulus (prominent seed catkins, another great street tree)
  8. Rhus typhina (huge staghorn sumac fruit cluster)
  9. Metasequoia glyptostroboides (one of the few evergreens that loses its needles; sports gorgeous tree bark)
  10. Fagus sylvatica (four seeds fit nicely into each pod, once they dried out at home they popped their seeds)


Tree topping requests

By | Arborist Insights, Landscaping | No Comments

Tree topping requests never go away. Never. Case in point. A strata owner in Maple Ridge walks up saying it’s time to “trim” his trees. (I prefer the term prune; trimming sounds suspicious.) So off we go to check it out. Outside his backyard fence -all of it belonging to strata- stand two perfectly healthy trees: Acer rubrum and Liquidambar styraciflua.

The key issue

The owner is upset because Mt. Baker is no longer clearly visible from his back balcony. He wants the trees “trimmed” to the level of his deck. Roughly 30% off the top, which means topping. He invites me to his house to see for myself. I decline. Since I signed ISA’s code of conduct, I am obligated to inform him that topping trees is a horrific idea. He doesn’t care. This is about his view.

Why is tree topping bad? (Get a complete pdf file here.)

  1. The trees produce weakly attached pseudo-branches from the top cuts which gets insurance companies very excited. Weakly attached branches tend to fail.
  2. It leads to decay.
  3. It leads to sunburn.
  4. It stresses the tree.
  5. It’s ugly.
  6. It’s expensive.



The owner of the corner unit wants both trees “trimmed” to the level of his patio….



The City of Maple Ridge is unlikely to allow a massive crown reduction on two perfectly healthy trees.


Strata letter

One week later the same gentleman produced a letter from his strata council stating that it was OK to trim his trees at his landscaper’s discretion. The future health of both trees had to be accounted for. As it turns out, the City of Maple Ridge has new tree bylaws from January 2016. Topping is clearly prohibited. Of course! Tree can be removed if they are deemed dangerous or in poor health, after city inspections to confirm this is really the case. There are fees to pay and replacements to install.


The best we can do as landscape maintenance professionals responsible for the site is thinning of the tree crowns. It would not hurt the trees and it would partially recover the owner’s view of Mt. Baker. Perhaps he will invite us in for tea?