Transpiration – Why you need to water your trees

Watering Can
Watering Can (Editor_B, Creative Commons)

By Brighton West

Trees need water. That’s why Friends of Trees staff and volunteers tell every new tree owner to give new trees 10 to 20 gallons per week during the dry season. We’re glad to see lots of ooze tubes and five-gallon tree-watering buckets around Portland.

But did you ever wonder why trees need so much water?

First, let’s look at photosynthesis. Water + Carbon Dioxide = Plant Material + Oxygen. You probably knew that already. Plants need water to make oxygen.

But there’s more—a lot more. It turns out that only ten percent of the water that’s sucked up by a plant’s roots is used for photosynthesis. The rest is used for transpiration.

Through transpiration, water evaporates from the undersides of leaves and is drawn up from the roots. This process cools the leaves, exchanges oxygen and carbon dioxide, and moves nutrients up the tree.

No water in the soil = no cooling of the leaves = no nutrient transfer and no photosynthesis.

So water those trees when it’s dry outside. And if you want a more detailed explanation of transpiration, complete with words like stomata, xylem, and lysimeter, check out Wikipedia.

–West is Program Director for Friends of Trees.

Everything you could want to know about the ooze tube

By Kate Farrington

How an ooze tube should be
How an ooze tube should look (FOT file)

So, what is an ooze tube? It is a nifty little drip irrigation bag you can purchase for $20 from Friends of Trees to help water your trees in the summer months! If you have trouble remembering to water your tree, or you are a landlord and don’t get to visit your tree very often, the ooze tube allows you to only water every two to three weeks, instead of once a week.

And ooze tubes are super easy to install! Check out our video, which walks you through how to install your very own ooze tube.

Have an ooze tube but are concerned about that cut in the top of the bag? You are not alone. But there’s actually nothing to worry about! This cut is the opening that allows you to fill the bag with a hose. Above is a picture of what it should look like. If your bag is actually damaged, please let us know and we’d be happy to replace it.

If you would like to purchase an ooze tube, just drop by the Friends of Trees office at 3117 NE Martin Luther King Jr Blvd, Portland, between 9:00 am and 5:00 pm. Someone in the Neighborhood Trees program will be happy to help you purchase your ooze tubes.

–Farrington is a Neighborhood Trees Specialist with Friends of Trees.

Ooze Tubes unravel mystery of summer watering

The secret of the Friends of Trees Ooze Tube
The Friends of Trees Ooze Tube makes water travel through several tiny holes previously thought to be invisible to the naked eye. (FOT file)

What costs $20, rhymes with ‘snooze,’ and lets homeowners sleepwalk through their summer time tree watering duties?

The Friends of Trees Ooze Tube, on sale now, is simple to install and relies on possibly even simpler technology that guarantees adequate tree watering for up to three weeks.

Friends of Trees plants several thousand new trees in Portland every year and even has a corps of Summer Inspectors who check on the health of young trees. The reality is that neglect happens, and in the dry summers it can lead to death for a tree.

If watering at least twice a week is not an option during the summer, homeowners should consider a drip irrigation system like the Ooze Tube for their watering needs.

Basically, each Ooze Tube comes with two special emitters that force water to travel through an elongated maze, ensuring that a very slow, continual drip absorbs into the tree’s surrounding soil.

Watch below for instructions on how to install, and call 503-282-8846 to order your Ooze Tube today!

–Toshio Suzuki

Tree curriculum: September events

Come downtown Friday afternoon and learn how to make seed bombs, or check out this photo tutorial. (LA Times)

Sept. 18, Friday 9 a.m. -3 p.m., is Park (ing) Day with Friends of Trees

Stumptown, 128 SW 3rd Ave.

One-day global event demonstrates the value and need for natural green spaces in the city . Friends of Trees will transform a downtown parking space into a green oasis, with real grass and trees. Come taste the stump, make some seed bombs, and learn how to enhance our urban canopy. 

Sept. 19, Saturday 11 a.m. -6 p.m., begins the Alberta Street Fair with Friends of Trees

Northeast Portland cultural event includes opportunities to meet local organizations. Stop by the Friends of Trees’ booth and ask some tree questions or learn how to volunteer at your neighborhood planting. For more information, please contact Andy at 503-282-8846 ext. 24 or

Sept. 20, Sunday 11:30 a.m. -3 p.m., is Friends of Trees’ Volunteer Picnic

Colonel Summers Park, SE 17th & Belmont

Friends of Trees invites its amazing volunteer corps to an afternoon treat of food and drinks. Come chat and play kickball in the sun before our 20th anniversary planting season begins. Please RSVP to Mary Harrell at

Sept. 26, Saturday 8:30 a.m. -3 p.m., is GSI Crew Leader Training

Brown’s Ferry Park, 5855 SW Nyberg Lane, Tualatin

Learn the necessary skills to lead crew for Friends of Trees’ Green Space Initiative program (formerly Natural Area Restoration). Training is free but space is limited. GSI crew leaders manage plantings of native trees and shrubs for both small and large scale plantings.

Sept. 26, Saturday 10 a.m. -4p.m., is the Welcome the Rain festival with Friends of Trees

Rigler Elementary School, 5401 NE Prescott

Visit the Friends of Trees’ booth and learn about how much storm runoff trees absorb every year at this local water conservation event and rain celebration. Free workshops will cover: rainwater harvesting; how to build an ecoroof; wet bicycling; disconnecting downspouts; and much more.

Sept. 29 to Oct. 17 is Tree Steward training with Portland Public Parks & Recreation

Seven session course covers general and advanced arbor care, tree biology, identification, planting and preservation. Once trained, neighborhood tree stewards work with PP&R staff on tree projects. Class is for ages 14 and up and costs $25.

For more information on any of these events, please contact Andy Meeks at 503-282-8846 ext. 24 or For even more information, please contact Greg Tudor at 503.282.8846 ext. 12, or

Trees, like humans, need water

In the summer, and even during a rare spring heat wave in Portland, Friends of Trees works to keep its trees alive with watering and pruning. Often this means Senior Neighborhood Trees Specialist Cain Allen is driving around a 425 gallon water tank that looks like an upside down jacuzzi in the back of a Ford pickup truck.

Yesterday, Allen, wearing the baseball cap, and NT Specialist David Odom, visited 13 Rocky Mountain Glow Maples and a pair of Paperbark Maples on Northeast Glisan.

Step 1: Get water
Summer watering: Neighborhood Trees

Summer watering: Neighborhood Trees

Step 2: Water & prune
Summer watering: Neighborhood Trees

Summer watering: Neighborhood Trees

Repeat steps.

Depending on when the rainy season comes, Allen said his watering time frame is usually May to October.

“We had a hot spell during the spring and some of the trees got fried,” said Allen.  “It’s just some of the leaves got toasted a little, but it’ll be fine.”

Fine, that is, thanks to FOT staffers and one Ford F-350.