Good Treehouse Timber

These trees are good treehouse choices, say arborists Alden Kelley and James Barry, who are often contacted by homeowners to determine if a specific tree is structurally sound for a treehouse.

Before building the treehouse, consider getting a civil engineer to draw up plans and see if the city you live in requires a permit.

* Avocado

* California sycamore (Platanus racemosa)

* Camphor tree (Cinnamomum camphora)

* Cape chestnut (Calodendrum capense)

* Catalpa (Catalpa bignonioides or C. speciosa)

* Chinese elm (Ulmus parvifolia)

* Coast live oak (Quercus agrifolia)

* Evergreen pear (Pyrus kawakamii)

* Holly oak (Quercus ilex)

* Lemon (large-sized)

* Lily-of-the-valley tree (Crinodendron patagua)

* Modesto ash (Fraxinus velutina ‘Modesto’)

* Mulberry (Morus alba, fruitless varieties)

* Olive (Olea europaea)

* Pecan (Carya illinoensis)

* Sawleaf zelkova (Zelkova serrata)

* Southern California black walnut (Juglans californica)

* Tulip tree (Liriodendron tulipifera)