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!).
It’s hot out there! In our service area and around the world we are experiencing unprecedented weather events as a result of climate change, including a recent heat dome with multiple triple-digit days. Here are some helpful tips to help your new trees weather the heat!
In general trees in our area need water from April to October, depending on weather. As you may know, extended hot, dry weather can place a great deal of stress on trees. Fortunately, just a little extra care will provide your trees the relief they need to minimize drought stress and keep them healthy. Follow these simple steps to ensure your new trees have the support they need:
Established trees: Give them a monthly soak, perhaps an hour on a drip line, or more if the tree appears stressed (e.g., dropping leaves).
New trees (in the ground 1-3 years):
WATER: During an excessive heat event, we recommend that you double your normal watering routine. This means that your new trees should receive 15 gallons of water at least twice a week throughout the heat wave, meaning a deep watering every three to four days when it’s about 90-degrees or more for an extended period.
The best time to water is in the early morning or after the sun goes down to minimize water loss to evaporation. Water slowly so that moisture soaks deeply into the soil and doesn’t run away from the root zone. This can be achieved using one of the following methods:
- A slow-release watering bag
- A DIY 5-gallon bucket drip system (check it out in the video above)
- Trickle your hose within the root zone for 15-20 minutes
Be mindful that it is possible to overwater your trees as well (though unlikely during the Portland region’s dry summers, overwatering is more common when folks water trees in winter. Allowing the soil to completely dry out—or allowing it to stay soggy—will result in a tree that is stressed. Deep, infrequent watering is the way to go: Water deeply, then hold off. Healthy roots follow the water downward as it starts to dry and establish sinker roots for increased drought tolerance. Keeping the soil consistently moist through deep and infrequent watering is essential to healthy trees. Wondering if it’s time to water? If you poke a pencil 4-5 inches down, does it come out dry & dusty? If so, water!
MULCH: Organic mulch is a highly effective way to keep the soil from drying out quickly, especially during excessive heat. A thick layer of mulch from wood chips and ground leaves is even better: Wood is essentially carbon and carbon is nature’s sponge, and leaves are like vitamins that are taken into the roots and are water-soluble. What we offer at the FOT Portland office is ground up branches and leaves combined, just like what’s found on the floor of a healthy forest.
“I like to remind folks that the forest floor is perfectly mulched and your street tree should be, too!” Andrew Land, Neighborhood Trees Senior Specialist
Mulch around the base of the tree will help to retain soil moisture and regulate soil temperature, which is exactly what roots need to grow. Apply mulch for a newly planted street tree using the 3-3-3 rule: mulch should be at least 3″ deep, 3′ in diameter, and pulled at least 3″ from the base of the trunk. If your tree is beyond that first year, you can extend that mulch further because our objective is to mulch the tips of the roots as they grow outward from the trunk. Three-inches thick is also important because it’s insulation (imagine the difference between a wind-breaker and a down jacket, for example: that dead air space matters.)
PRUNING: Generally it is safe to prune most trees in mid-summer, from roughly mid-July to mid-August to be more specific. However, you may want to pause pruning during an extreme heat event, including right before and right after an extreme event, so consult the weather forecast as part of your pruning plan. Check out our pruning page for lots of useful information, including how-tos.
We’re seeing some gorgeous sunny spring days recently, which means…it’s time to start watering your young tree(s)! A newly planted tree needs at least 10-15 gallons of water each week from roughly now until late September for the first three years in the ground to ensure that they thrive going forward. Providing one deep watering over the entire root system per week is recommended. You can think of it as giving your tree a weekly rain shower – every Saturday morning, for example. If we have approximately 90-degree or warmer weather consistently or if your tree shows any signs of being thirsty (wilting, browning leaf margins, etc), it wouldn’t hurt to double up and water both Tuesday and Saturday that week.
There are a number of different ways to make watering easier. You can easily construct your own 5-gallon bucket drip system or purchase a 15-gallon slow-release watering bag (such as a gator bag). Please note we no longer will be offering these from the Friends of Trees as we have in years past, but that is because they are readily available online and in local hardware and garden stores. Also, be sure to check out our Tree Care page to get all the details on taking care of your new investment.
Remember that weeds and grass compete with your tree for water. Please maintain the mulch for your tree(s) and hand pull weeds. When you mulch, be sure that there is a 3-6” radius from the base of the trunk of the tree that is free of mulch. You want that space clear so there’s no moisture held at the base of the trunk, which can rot the tree’s root crown. The moisture held by mulch should be above the growing root tips as they grow outward from the trunk, for the most part within about 18″ of the soil surface. Also, please be careful not to damage the tree bark with lawn mowers, weed eaters, or car doors. The bark is what contains a tree’s water and nutrient transportation system; it also keeps insects and diseases out.
We have volunteer Summer Inspectors out visiting every street and yard tree planted in the previous season, and they keep us informed on the health of the trees we plant. If you have a tree that isn’t looking so great, please trust that after Summer Inspectors complete their routes this summer we will then determine if staff needs to check on your tree.
Portland Urban Forestry recommends an annual root pruning for trees planted in the streets, especially those in narrower planting strips, to discourage roots from growing under sidewalks. Here is a link to learn more.
Pay it Forward! Friends of Trees couldn’t reach our high goals without supporters like you. In order to continue providing tree discounts and plant in as many neighborhoods possible, we need your help! Please consider making a donation to help us grow our urban forest for both this and future generations.
Hopefully we’ve answered your questions and you’ve found these links helpful, but feel free to contact us if you have any questions at 503-595-0212 or email me at AndrewL@FriendsofTrees.org .
Pruning trees contributes to a more equitable community. Or, more accurately, pruning trees at no cost contributes to a more equitable, livable community.
How? We’ve learned that a major barrier to many households getting a street tree is the cost of maintaining the tree. Pruning can be very expensive, and it gets more expensive as the tree ages and grows if problems are not addressed early. Properly pruning a tree when young is an excellent investment and can delay or even prevent future expenses, making a tree more affordable. Pruning young trees at no cost by trained Friends of Trees volunteers is one important way to help get more trees into more neighborhoods, especially under-served, low-income communities which are often communities of color impacted by systemic disparities. That is exactly why Friends of Trees is focusing efforts on specifically those communities who will benefit the most.
Our pruning program also benefits youth through our educational partnerships. While we are pruning trees we are also training young people to prune. Through partnerships with organizations like Rosemary Anderson HS POIC, student interns in our pruning program earn an hourly stipend while building valuable job skills. Pruning skills can be developed and honed in preparation for becoming an ISA-certified arborist – a very solid living with excellent job security. Added bonus: Exposing young people to the benefits of trees and tree care contributes to a greater appreciation of trees and nature, helping to grow the next generation’s Tree Team.
Pruning = longer lived, healthier trees = healthier planet + people. The benefits of trees—oxygen creation, pollution and stormwater absorption, healthier humans (DYK that trees help combat cardiac and respiratory ailments and can even contribute to increased birthweights?), and so much more—increase exponentially as trees grow and age. And the earlier a tree is properly pruned, the greater the chance it will grow to a ripe old age benefitting neighborhoods and the planet for generations to come.
Pruning for structure (shape) and clearance (sidewalks and streets) is the primary way to steward and care for a tree post-establishment. Proper pruning contributes to the long-term health of the tree, while lack of pruning, or pruning incorrectly, will contribute to the premature demise of the tree. Pruning in the built environment (as opposed to a natural setting) is also key to preventing tree-related damage following inclement weather.
There’s another reason pruning young trees is better: It’s easier for the tree to recover from pruning when it’s young than it is when the tree is more mature (trees have to “recover” after any sort of pruning, good or bad, it’s just far more efficient for them to recover from careful “surgery” by a trained pruner as opposed to “natural” pruning by snow/ice + wind). When pruned, a tree immediately gets to work “sealing” the cut, working to close off the wound.
When pruning young trees, we have the opportunity to make a 5-cent cut today to prevent the need for a $100 cut 20 years down the road (or, so the saying kind of goes ;). Not only is it more cost-effective to properly prune young trees, the larger the pruning cut (because the limbs are larger), the longer it takes the tree to recover. A tree can quickly seal and move beyond a ¼” cut made with hand pruners, but it may takes years to recover from an 8” diameter cut made with a chainsaw (and it may never recover at all). BTW, trees don’t actually “heal,” they seal or compartmentalize and – once recovered – they then grow more vigorously.
With all the benefits of pruning it’s a good thing our pruning program is so popular with volunteers (100+ pruning volunteers every year!), since volunteer-power is the only way we’ll be able to prune 2,000 trees this season. Pruning is especially popular right now as it’s pretty pandemic-resistant: pruning is not a large group activity and it takes place 100% outdoors. In fact, it’s because of COVID that this will be the biggest pruning season yet, with a 40% increase in trees pruned over last season! BTW, we’ll prune any young street tree in our service area (6” diameter or smaller), not just the trees we plant – all at no cost (thanks in large part to our partners at City of Portland Bureau of Environmental Services).
Pruning trees properly contributes to the health of the tree and to those who live under its canopy. We of course want the trees we plant to grow and thrive, and proper pruning when young is key to tree health, so pruning is an important part of our Neighborhood Trees program. Need more information? Visit our tree resources page for more information about tree care and the benefits of trees. Ready for a tree of your own? Get started here!
Photo: Youth interns learning to prune, part of our Rosemary Anderson High School/POIC partnership; August 2020.
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.