Self-Guided Tree Walk: Barron Park

Tree Selection by Dave Muffly, ISA certified arborist.
Updated by Jana Dilley and Marty Deggeller, summer 2003
Additional information gathered from the Sunset Western Garden Book.

Download this Tree Walk (PDF Version)

The Barron Park Tree Walk Tour begins at the intersection of La Donna Street and Los Robles Avenue.

1. Valley Oak (Quercus lobata)
~ 3975 La Donna St., right of driveway
“California’s mightiest oak,” according to Sunset’s Western Garden Book. A valley oak should determine the other landscaping around it, since watering of plants around its roots can cause root crown fungus, leading to falling limbs and death of the tree. This battered specimen may need to be removed after a life of over 200 years. If it is gone, look for another valley oak example on the property to the left when facing the house; it’s entwined with a blackwood acacia.

2. Valley Oak (Quercus lobata)
~ 719 La Para Avenue, right of driveway and right of sidewalk
These two younger trees may reach a height of 70 feet or more, with an equal spread. Planted in about 1960, these trees illustrate how a valley oak planted today will grow and develop over time. With good care and regular watering, native oaks can grow quite quickly when young. The acorns from valley oaks were a favored food of California native peoples who leached out the tannic acid and found a nut with lots of carbohydrates and little fat. Another magnificent specimen can be seen at 3775 La Donna Street.

3. Aleppo Pine (Pinus halepensis)
~ 833 La Para Avenue, right of driveway
Thanks to a caring owner and the excellent growing conditions in Barron Park, this tree is unusually large for its species. The Aleppo is native to the Mediterranean region and grows 30 to 70 feet high with a variable canopy shape. These fast-growing pines are well adapted to our climate, as this tree (one of the tallest in Palo Alto) demonstrates.

4. Blackwood (or Black) Acacia (Acacia melanoxylon)
~ Between 889 and 891 La Para Ave.
The evergreen black acacia is common here in Barron Park. These tough trees can grow fast and dense, up to 60 feet with a 40-foot spread. They are supremely well adapted to our climate, and young black acacias start readily from the seeds of parents. The roots are aggressive and can be a problem, especially in confined spaces.

5. Japanese Pagoda Tree (Sophora japonica)
~ 930 Los Robles Avenue, to right of driveway across the creek
Growing in the deep, creekside soil with lots of available water, this is a large and beautiful specimen of a species sometimes planted as a Palo Alto street tree. They are usually smaller, growing 20 to 25 feet tall with a similar spread, and residents sometimes complain about the liquid from their seed pods which will stain carpets. In Japan, these trees are often planted around Buddhist pagodas.

6. Honey Locust (Gleditsia triacanthos)
~ 4079 El Cerrito Rd. on Cerrito Way, next to walkway to the left of the house
These deciduous trees are native to the eastern US and are widely planted there as street trees. Their €ne leaflets produce a dappled shape. They grow to 35 to 50 feet with a similar spread. They can make a good lawn tree, producing light shade.

7. Camphor Tree (Cinnamomum camphora)
~ Rows of street trees starting at 911 Ilima Way
This street shows how planting one large species along both sides creates a “tunnel” effect. Camphors often spread out to a width as great as their height, creating a shady canopy. These trees are native to Japan and China and may grow up to 50 feet. They have glossy light green leaves and furrowed bark. The trunks of these trees spread very wide and roots will readily crack nearby pavement. They can be damaged by freezes and are susceptible to verticillium wilt. These trees are evergreen, so plant with care to avoid blocking winter sun.

8. Red Maple (Acer rubrum)
~ 3618 Laguna Ave., 5 street trees
This tree is native to the eastern United States and grows to 40 feet with a 20-foot spread. The property owner here has planted these tree with a uniform spacing which will be interesting to watch as the trees mature. These trees are known for their red fall color.

9. Pecan (Carya illinoensis)
~ 3675 La Calle Court, corner of Barron Avenue and La Calle Court
Native to the US south and Midwest, these fast-growing nut trees can attain 70 feet with a spreading canopy. Edible nuts from pecan trees are a rarity in our climate; although the trees will sometimes set nuts, summer temperatures here are not high enough for the nuts to harden off. And even if the nuts would form properly, the squirrels would beat you to them!

10. Camphor Tree (Cinnamomum camphora)
~ 814 La Jennifer Way, left of driveway
This specimen shows well the beautiful symmetry of the camphor when grown alone.

11. Chinese Pistache (Pistacia chinensis)
~ 820 La Jennifer Way, left of driveway; This is the tree near the street number sign.
This example is not yet mature but shows the very spreading and symmetric tree form these trees are known for. Beautiful in the fall, foliage becomes scarlet, crimson, orange, and sometimes yellow. These moderately growing but highly adaptable trees can take lawn water or dry soil. Tree can grow to 30 feet tall with a 30-foot width. Usually a reliable street or lawn tree.

12. Coast Live Oak (Quercus agrifolia)
~ Between 841 and 838 La Jennifer Way
This wonderful, large specimen is planted directly on the property line. The homeowner estimates that it was planted around 1955. The coast live oak is an evergreen native throughout much of California. They grow relatively quickly to 70 feet with an equal spread. Once established, they take drought well. The acorns that drop in the fall can produce young live oaks very readily. As you may see, the live oak casts a dense evergreen shade that can block the warming winter sun, so thoughtful planting is recommended. Native oak trees thrive on neglect: summer watering, construction, or soil compaction around the roots of the tree can spell doom.

13. Cork Oak (Quercus suber)
~ 3785 El Centro St., front yard right of driveway
This wonderful example of the cork oak, with a coast live oak to the right of it, shows clearly the differences between the two. The cork oak is an evergreen tree native to the Mediterranean, and if you look closely at the trunk of this tree, you will see that you can thank this tree for the cork in your wine bottle. This tree can grow to 50 feet with an equal spread. Needs good drainage or it will yellow. Very drought tolerant once established.

14. Copper Beech (Fagus sylvatica ‘Atropunicea’)
~ 3756 Cass Way, backyard, right of house
These purplish deciduous trees can grow to 90 feet but are usually smaller. They have smooth, grey bark.

15. Chinese Elm (Ulmus parvifolia)
~ 706 Barron Avenue, front yard
These beautiful, graceful trees can be evergreen or deciduous, depending on temperatures. They grow rapidly to 40 to 60 feet tall with an equal or greater spread. Chinese elms vary in shape but usually appear spreading with long weeping branches that reach down to the ground if not pruned. This one is well pruned. Although these fast growing trees are well-adapted to our climate and were extensively planted in Palo Alto as street trees, the City no longer plants them because of the high cost of regular pruning to keep the foliage off the ground. These trees have few pest or disease problems.

16a. California Pepper Tree (Schinus molle)
~ 696 La Donna St., on Barron Avenue, overhanging the road
A native of Peru, this fast-growing tree can reach 40 feet with an equal spread. Its weeping canopy contains bright green, narrow leaflets and many yellowish white summer flowers in drooping 4- to 6-inch clusters. Flowers become rose-colored berries in the fall. The gnarled and deeply furrowed trunks of these trees grow quite large and are best in unconfined spaces. Strong surface roots can cause damage if planted too close to buildings or pavement. These trees are drought tolerant, but have some disease problems. You can see an even larger specimen behind you at 3721 La Donna Street.

16b. Fig (Ficus carica)
~ 696 La Donna Street, at the back of the property along Barron Avenue
This mound of a tree grows wide onto the road, showing its large, distinctive leaves. It can also be identified by its smooth, light-grey bark. The fig is well adapted to our climate and generally produces copious quantities of fruit. Figs can grow quite
large, but may be kept to a manageable size and shape with pruning, which is best done in the summer.

17. Black Locust (Robinia pseudoacacia)
~ 581 Barron Avenue, parking area front of fence
This young black locust shows the potential of this species for producing rapid shade. These fast-growing deciduous trees grow to 75 feet. Native to the eastern U.S., this tree has “naturalized” in many places, including our area. They have lacy, bright green compound leaves and in the spring produce large quantities of nectar-filled white flowers that are well-loved by bees. Black locusts are also legumes and can enrich the soil. The bark is gray with deep furrows. In their wild, uncultivated forms, these trees have been discontinued as street trees in part because of thorns on their branches.

18. Chinese Tallow Tree (Sapium sebiferum)
~ 730 Paul Avenue, front yard, left side
This tree is known for its dramatic red, yellow, or purple fall color. Sapiums grow to 35 feet with an upright, rounded canopy and lovely heart-shaped leaves. They give light-to-moderate shade and can grow fast when given plenty of water. The name “tallow tree” is derived from the Chinese practice of using the waxy coating around the seeds for making candles.

19. London Plane Tree (Platanus acerifolia)
~ 751 Paul Avenue, on the right side of the property
This is an excellent, not-yet-mature London plane. Planes are common street trees all over America because they “rise above the indignities of smog, dust and automobile exhaust,” according to Sunset, and may reach 80 feet high by 40 feet wide. They also tolerate drought quite well. You can see an entire street of London planes on Amaranta Avenue starting at Los Robles. The trees there are 40 to 60 years old and may be considered mature. A disease called anthracnose is common in older varieties of London planes, but those planted today are bred to be resistant.

20. Big-Leaf Maple (Acer macrophyllum)
~ 3880 La Donna Street, left of driveway on San Jude
Another tree native to the west coast. These broad-topped, dense, deciduous trees do well as street trees in areas with deep soil. They grow 30 to 50 feet. Notice the large, dark green leaves on this tree and the lightly furrowed grey bark. They grow quickly to form a symmetrical, rounded canopy. This specimen is thriving on the extra irrigation from the lawn. These trees are adaptable; at 800 Matadero, another fine example is growing well in a low-irrigation area along the street. Big leaf maples in their native environment can be seen along the upper stretches of Alpine Road in Portola Valley.

This publication was funded by the California ReLeaf 2003 Capacity-Building Grant Program and the California Department of Forestry and Fire Protection.