watering with a bucket

Determining Your Tree’s Watering Needs

We’ve had a wet April, which means your trees are getting plenty of water! But the transition from spring to summer can be a tricky time to determine when to water your tree.  Come this time of year, we recommend watering once a week when the weekly rainfall is less than one inch. But you might find yourself wondering, “when did it rain last?” (You can check here!)

Too much watering is the most common mistake, but consistent watering is crucial to getting these young trees established. A good way to know if your tree needs water is to check the soil. Stick a garden trowel or even a pencil 2-3 inches into the soil. If the soil at that depth is dry to the touch, then your tree is ready to be watered.

watering crew

Once the dry season settles in, watering once a week is a good schedule (pick a day to water and keep it up!). Deep watering is best for these newly planted trees. Give 10-15 gallons at a time. Water slowly so that moisture soaks deeply into the soil and water doesn’t run away from the root zone. Mulching is a great way to hold water in the soil for your new trees.

Either a gator bag, hose on a gentle trickle for maybe 20 minutes, or a 5-gallon bucket with three 1/8″ holes drilled on the side at the bottom and filled 2-3 times consecutively works great. It’s a good practice to move the bucket around the tree each time you fill it to ensure that the whole root system gets water. Think of it this way: we’re trying to simulate a rain storm, during which all parts of the root system will get water at about the same time and rate.

It’s important to note that dry and hot are two different things. In late spring and early summer, we may get some seemingly perfect weather, and you don’t think to water your tree because it isn’t hot outside. But regardless of temperature, a dry spell is characterized as 2-3 weeks without significant rainfall. It might not be hot out, but your tree still needs a drink!

If the temperature gets over 90 degrees, bump your watering schedule up to twice a week. If we see another heat “event” coming, a good, deep soak beforehand can help the tree survive.

Leaflet: Spring Tree Care

Spring has Sprung – What that means for your trees

Trees are breaking dormancy, but that doesn’t look the same for every species. Some are early risers, and some sleep in. A bunch of factors go into it, including species, daylight, and temperature. Here are some things you can do to take care of your trees this time of year.

Mulch Madness

It’s a great time to refresh mulch as needed. The objective is to mulch the tips of the roots as they grow outward from the base of the trunk. They will grow into soil that’s moderate in temperature and contains moisture, factors that mulch will provide. Because the roots are growing outward, when you mulch trees in their second year in the ground, aim for more of a 4-5′ diameter ring of mulch, still 3” thick, about a foot from the base of the trunk.

You may have noticed that some trees hold their leaves through winter. They’re called marcescent leaves, and they are a sign of last season’s growth. You’ll see them on native oaks like Oregon white oak (Quercus garryana) and scarlet oaks (Quercus coccinea). Come spring time’s flush, these leaves will be shed to make room for new growth. You can use these leaves as mulch!

Go easy on the pruning

It’s best to go easy with regard to pruning during “bud break.” This is when sap is rising up the tree, after having dropped to the roots in the fall. As the sap is rising, some trees (maples, for example) will “bleed” if pruned as sap is rising. It’s not harmful to the tree—that’s where maple syrup comes from, after all—but it can be disconcerting to see.

Weekly Watering

It’s almost time to start weekly watering for newly planted trees. “Deep and infrequent” is the recipe for success. Starting mid-April, 15 gallons all at once, once a week is ideal. Either a gator bag, hose on a gentle trickle for maybe 20 minutes, or a 5-gallon bucket with three 1/8″ holes drilled on the side at the bottom and filled 2-3 times consecutively works great.

If the temperature gets over 90 degrees, bump that up to twice a week. If we see another heat “event” coming, a good, deep soak beforehand is very wise as preventative medicine.

More tree care here!

Tree Care + Equity

Most people by now are fairly well attuned to the benefits of trees environmentally, socially, mentally, and more. However, less people are aware of how tree canopy is distributed among a city and its neighborhoods.

A trend across the country in large cities is that trees, and the benefits they bring, are distributed inequitably across neighborhoods based on race and income. Higher income neighborhoods with majority white residents have over 75% tree canopy coverage as compared to lower-income neighborhoods with around 15-30% canopy cover. These are large discrepancies that result in hotter environments, more air pollution, and factors contributing to respiratory conditions like asthma for children.

These trends are reality here in Portland: west Portland (excluding Forest Park) has about 75% canopy cover in most neighborhoods, while east Portland neighborhoods average about 15-30% canopy cover. Friends of Trees prioritizes planting street and yard trees in neighborhoods on the eastside of Portland to help decrease this disparity.

However, many people are wary about – if not outright opposed to – getting a tree of their own because of the costs of tree care, which can increase as a tree grows. This is just one of the reasons Friends of Trees provides tree care along with tree planting, including proper pruning of young trees at no cost to the property owner. And we’re exploring ways to increase the availability of low to no cost tree care for folks who need it, because we know the benefits of trees far outweigh the costs.

In the City of Portland, tree care and maintenance costs are the responsibility of the tree’s adjacent property owner. This is an inequitable financial burden for low-income households, renters, and populations vulnerable to gentrification. Many communities of color cite the financial burdens that a mature tree can bring as a reason to not want to plant trees next to their houses. It’s important to address these very valid concerns since trees have so many benefits, which is why Friends of Trees is continually working on creating programming that is responsive to community needs; in fact, we have funding proposals pending with Portland’s Clean Energy Fund that would help subsidize costs of mature tree care so we can grow our already considerable post-planting tree care services.

Understanding concerns about tree care
In 2018, Friends of Trees partnered with APANO and LARA Media to conduct three focus groups toward better understanding how community members viewed neighborhood trees and tree planting efforts. To increase accessibility these focus groups were conducted in multiple different languages including Vietnamese, Mandarin, and Spanish. Overall, many community members cited the benefits of trees within the city, including their health and environmental benefits:

“Trees are good for the lungs. They are the lungs of the city.”
“In the city, there’s big trees that make the air cooler. It also makes the city greener.”
participants from the Vietnamese focus group

However, when asked if there are barriers for them to plant trees, many community members cited the long-term costs associated with mature tree care. One participant said: “One of the negatives is that sometimes Portland has a lot of storms and trees fall down when there’s strong wind. I experienced that once. The tree can fall into the house and collapse the house. Usually I try to hire a professional to cut the tree, but it [can cost] thousands of dollars. The tree bothers us.”

Trees and access to the natural environment are integral to healthy, livable neighborhoods. The benefits trees bring are strongest when they are mature, at least 10-15 years after they are planted. However, the fears community members have about the costs trees may bring are also valid, especially since the median household income on the eastside of Portland is lower  and there are fears of being pushed out.

Friends of Trees is committed to equitably growing the urban forest through community-centered tree plantings. We offer tree care for the first three years of a tree’s life after it’s planted, including affordable (or free if cost is a prohibiting factor) summer watering service; free mulch; and structural pruning provided at no cost (see the next story for more about our pruning program). Structural pruning on a young tree is vital for its long term health, and can help prevent limbs falling onto a house or car later on in its life, since we can prune for the built environment and the tree will grow into that structure.

However, Friends of Trees also recognizes there are long term costs and concerns that need more support within our communities to make sure the urban forest is distributed equitably. We are continually working on creating programming that is responsive to community needs and when the opportunity arises we pursue grant funding to help subsidize costs of mature tree care. Because we know that, all in all,  the positives of trees far outweigh the negatives; as our good friends at J Frank Schmidt like to say, “Trees are the answer.”

Photo: Street tree planting in east Portland, January 2020.

Leaflet: Prepare Your Trees For Winter

Pruning techniques to make your trees more resilient to winter storms

The temperatures have dropped, and it’s probably just a matter of time before we get some serious winter weather. The best thing we can be doing this time of year to make our trees more storm resilient is pruning. We’re going to walk you through the pruning techniques that will help a tree if and when we get another serious winter storm. 

As we’ve seen more and more in recent winters, the combination of wind and ice will lead to branch failure—in short, nature prunes itself. That’s exactly why it’s best to prune problem areas now rather than waiting until snow and ice is predicted. Ice can increase the weight load on a branch by up to 30 times.

For an even more in-depth guide to pruning, visit our pruning page.

Prune outside the branch collar. The most important technique when pruning any branch, whether it’s a quarter-inch or four inches diameter, is to prune just outside the branch collar. On some types of tree, the branch collar is obvious. It is that bit of swelling—like a collar—at the base of where the branch connects to the trunk. That swelling is an accumulation of healing hormones. If you cut flush against the trunk, you’re cutting away the hormones that will close it off and protect it from pests and diseases.  

Remove the Ds. The best way to start is to look for branches that are dead, diseased, dying, or decaying— anything that starts with a D. Just take a nice pruning saw or or some hand pruners and prune that right out of the tree.

A small six- or seven-inch folding saw is really all that a homeowner needs. We could do 99% of what we end up doing with just hand pruners and a folding saw on a young tree.

Mind your pruning budget. You shouldn’t prune away more than 25% of your tree’s canopy. Leaves are effectively solar panels that produce energy for the tree, and you don’t want to remove too much of that. Sometimes people want to prune their trees to encourage it to grow taller, and they’ll prune all the lower branches and make a sort of lollipop. So another part of calculation is that two-thirds of the trunk needs to have lateral branches.

Dead and dying branches do not count toward that budget, because they are not producing energy for the tree. The tree wants to lose those anyway and, as we already mentioned, nature will more recklessly prune them away during the next storm if you don’t. Suckers—the small branches at the base of the trees—should also be removed. While they do have leaves, they also do not count toward that budget, because they could become so vigorous that they just take over. 

Look for included bark. A wide angle between a lateral branch and the trunk creates better architecture than a sharper angle. When the angle is more acute, the bark will start to fold over itself in the crease at the connection point. This is called included bark. Branches with included bark are where more than 80% of failures happen.

There might be instances where pruning all the branches with included bark will take you beyond your pruning budget, in trees like Japanese maples, zelkova trees, or columnar (upright) cultivated varieties. There are ways to address included branches without removing them entirely. You can cut away the most vigorous upright branches along the branch, which will stop that branch from growing more. There is a gravity-fed hormone in upright branches that encourages growth. By removing the upright branches, you change the hormones to those for repair and reproduction and in doing so, slow the growth of the branch relative to the trunk.

Encourage a strong central trunk. We’re trying to prune trees to have a strong central trunk—or central leader. Some trees, like conifers, grow a central trunk naturally. Other trees want to have a more rounded canopy. We want to create a strong backbone so that a tree is more resilient to wind. It is a bit unnatural, but when we are planting trees in the built environment, we have safety considerations to keep in mind. If a tree is in the middle of a giant backyard, it can take a more natural shape, but if it’s somewhere where its branches could fall on a house or a car, it’s helpful to have that strong central trunk.

When you prune, look for a strong central leader on a young tree that can be encouraged as it matures, and prune away competitive side branches. The rule of thumb is that you don’t want to have any lateral branches that are more than half the diameter of the central leader. By keeping those side branches smaller, if they fail, it’s less likely to be catastrophic to the tree or its surroundings.

If a storm comes!

When a winter storm does arrive, what do you do?  Shake off snow, but not ice. Light snow can be gently shaken from branches with a broom moved in an upward motion. Heavier snow and ice should be allowed to completely melt  because branches with ice especially often fail when shaken.

Once the snow is gone, inspect your tree for damage, taking care to take safety precautions as necessary. You can use a pruning saw to cut away any dead or damaged branches at the nearest branch collar.

Pruning resources:

  • We have an entire webpage on how to prune that gets into even deeper detail.
  • If you have a bigger tree, and the task of pruning it is beyond you, get in touch with one of these recommended arborists.
  • If you have a specific question that you just can’t crack, you can write our new email address for pruning questions: [email protected]


Fall Tree Care

Leave the leaves!

Fall brings cooler days and evenings, an extra layer when we head out, and the striking colors on display gifted to us by nature. For many of us fall also means raking leaves–but it shouldn’t. In fact, fall tree care should include leaving the leaves!

We have this habit as a society to rake and dispose of leaves, but leaves are vitamins for plants and magic for building the health and vitality of soil. Throughout the growing season trees are producing energy in the form of sugar, or, sap. This time of year, as we start to see the leaves changing color, that’s the indication that the sap is crawling from the leaves, into twigs and branches, down the trunk and into the roots for winter.

When leaves fall, much of the tree’s energy, in the form of sap, goes into the root system encouraging new root growth (FOT gets busy this time of year very deliberately: planting trees now gives the roots a head start and a chance to anchor themselves). The rest of the leaf energy falls from the tree and settles on the ground–these leaves are literally vitamins for the root system that is primarily about 12-18” below the soil surface.

When we remove leaves we are actually interrupting a process called nutrient cycling, which is when the leaves break down and feed the roots. Rain carries the nutrients downward and provides them to trees and other plants water-solubly. So, leave the leaves! At the base of trees, in your garden beds, anywhere you want healthy soil in the spring.


Mulching: it’s not just for spring

Think about it: the forest floor is perfectly mulched. The act of transplanting a tree is unnatural, what we do planting trees doesn’t happen in nature, they don’t jump around and move. So, as tree stewards, we are trying to make trees feel comfortable, to restore a natural setting–as much as possible, of course, in an urban area. Street trees have it tough in this regard: They are often in compacted soil that is depleted, and it’s depleted because, unlike in the forest, we often remove leaves and clippings, and soil gets very compacted in the built environment.

So in addition to leaving the leaves, refresh mulch as needed. Create a “sacred mulched zone” ideally 2-3 feet in each direction from the base of the tree; this should be and remain a grass-free zone, and it should be an area that won’t be disturbed. If the tree is in a small space, such as a street tree next to the sidewalk, maintain it in the form of a square if there’s grass to mow since it’s easier to mow along a straight line than around a ring of mulch.

Why mulch? 50% of healthy soil is air & water pockets. How do we get these pockets? Partly through roots, just the process of roots growing down. And when some of the roots die and decompose they leave space in their wake, where fungi and bacteria grow and bring life to soil. Those fungi and bacteria grow where the soil isn’t, which is why compacted soil can be a challenge to bring to life.

When trees are transplanted – the most stressful day of a tree’s life – we want to foster new growth to set the new tree on the path of health and vitality. Tree roots can grow year round as long as the temperature of the soil is moderate (think of mulch as a down jacket for the soil) and there is the presence of moisture, both of which are provided by mulch! One inch of mulch is a windbreaker, three inches is like a down jacket – and we want that year round, protecting against temperate extremes. Not only is mulch insulating, it’s also thirst-quenching since wood chips hold water.

Fall tree care should start with building the soil with organic matter through application of mulch, setting the tree up for success, which is ever more important in a changing climate. Do take some time to get your mulching and non-raking done, and then tune in next month when we share the next stage of your fall tree care (hint: it rhymes with strewn, but don’t start yet!).

Check out our website for more tree care information and resources.

Our friends at Chip Drop are a great source for mulch, learn more here!