Arbutus xalapensis. It occurs southward through Mexico into Guatemala [ 12 ]. Sapwood is light in color. The wood is easily worked and colorful [ 16 ] and reportedly has some commercial value [ 25 ].
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Arbutus xalapensis. It occurs southward through Mexico into Guatemala [ 12 ]. Sapwood is light in color. The wood is easily worked and colorful [ 16 ] and reportedly has some commercial value [ 25 ]. It has been used to make tool handles, rollers, fuel, and charcoal for gun powder [ 26 ]. Small plants with accessible foliage are lightly browsed by cattle [ 12 , 26 ]. Use by domestic goats may be heavy in some areas [ 19 , 26 ].
The sweet fruit of Texas madrone is eaten by many species of birds [ 19 , 26 ]. Berries are palatable to many species of birds [ 19 ]. Plants can also be grown from seed, although light and soil moisture requirements are exacting [ 12 , 27 , 28 , 31 ].
After more than 10 years of experimentation, only 2 of 10, seeds planted in carefully controlled greenhouse conditions actually germinated and became established [ 12 , 31 ]. Fortunately, newly developed laboratory techniques have greatly improved seedling survival rates [ 27 , 28 , 31 ] [see Regeneration]. Researchers recommend selecting seeds carefully, using sterilized soil and distilled or deionized water, supplementing natural sunlight with artificial light to extend daylength, and carefully controlling fungus [ 12 ].
Seedlings should never be exposed to direct sunlight until well conditioned. Details on seed handling and planting techniques are available [ 12 , 27 , 28 , 31 ].
Texas madrone is difficult to transplant [ 12 ]. The attractive leaves and flowers make it well suited for individual or mixed plantings [ 23 ]. The leaves and bark are astringent and are used medicinally in parts of Mexico [ 26 ]. Older, larger trees are dying, and few seedlings and young trees exist [ 23 ]. Seedlings are particularly rare wherever livestock are present [ 12 ], presumably because of the combined effects of browsing and trampling.
Managers interested in preserving this unique species may wish to protect the few locations in which seedlings have been found. This plant is also susceptible to a condition in which large limbs turn black and the foliage soon dies [ 12 ].
The causal agent has not been identified. Plants may reach 40 feet 12 m in height, 9. Branches are usually crooked, stout, and spreading [ 26 ]. Bark of Texas madrone is both unique and attractive. Older bark is dark brown, gray, or black and exfoliates annually in papery layers to expose colorful new "skinlike" bark [ 2 , 12 , 26 ].
New bark may be white, orange, pink, apricot, tan, or dark red [ 22 , 26 ]. The simple, alternate leaves of Texas madrone are thick and leathery [ 12 , 22 , 26 ]. Leaves are oblong to elliptic ovate to oval, dark green above and paler beneath [ 22 , 26 ]. The upper surface is glabrous, whereas the lower surface is glabrous or somewhat pubescent [ 26 ]. Small, urn-shaped white or pinkish-white blossoms occur in clusters or panicles approximately 3 inches 8 cm in length [ 12 , 22 ].
Fruits are nearly round, warty "berries" 0. Berries are bright red, yellow-orange, or yellow [ 22 , 26 ] and are borne in 2- to 3-inch cm clusters [ 26 ]. Each fruit contains 1 to 10 small white seeds [ 26 , 31 ]. However, this species is characterized by a low reproductive rate [ 23 ]. Seed is produced in abundance [ 26 ] and widely dispersed [ 19 ], but seedlings are extremely rare.
A unique population of several hundred seedlings reportedly exists near Vanderpool, Texas. Seedlings exhibit best early growth under a hour photoperiod at daytime temperatures of 81 degrees F 27 degrees C and nighttime temperatures of 64 degrees F 18 degrees C [ 27 , 28 ].
Good growth occurs at 60 to 70 percent relative humidity at a light intensity of 6, to 10, lux [ 28 ]. At higher light intensities, growth may be reduced by photo-bleaching of chlorophyll [ 27 ].
The effects of higher light intensities may be somewhat mitigated under natural conditions if soil moisture remains high [ 27 ]. Under ideal laboratory conditions, germination can range from 20 to 90 percent [ 31 ].
Other species can also serve as "nurse trees", but seedlings are rarely if ever found beneath older madrones [ 12 ]. The partial shade of the nurse trees reduces water stress and allows seedlings to survive despite dry conditions [ 28 ]. The heavy mulch also promotes survival by holding water. Stump-sprouts have been reported under natural conditions [ 31 ].
It grows well in full sun on xeric sites [ 22 , 26 ]. Texas madrone is a common component of closed-canopy canyon forests and densely wooded stands which occur at the head of canyons [ 11 ]. Scattered individuals occur in oak-pinyon-juniper and Madrean evergreen woodlands, interior chaparral, and ponderosa pine Pinus ponderosa communities [ 3 , 4 , 12 , 19 , 29 , 30 ]. Eastern cottonwood Populus deltoides , coyote willow Salix exigua , gray oak Quercus grisea , bigtooth maple Acer grandidentatum , and ash Fraxinus spp.
Soil pH commonly ranges from 7. Soils are often derived from limestone or igneous parent materials [ 26 ]. It occurs in relatively undisturbed climax riparian woodland communities. However, little is known about its successional role in other communities in which it occurs. In many areas, the narrow canyon forest contrast strikingly with adjacent desert grassland or shrubland communities [ 5 ]. Evidence suggests that recurrent fires in the much drier desert grassland types may have eliminated invading shrubs and trees [ 13 ].
Texas madrone also grows in moist forest communities of the Chisos Mountains of Texas in which fire-scarred trees are commonly observed [ 8 ]. The presence of both seedlings and mature 2 to 6 inch d. Limited establishment may occur on favorable sites from bird-dispersed seed originating on adjacent unburned sites. Postfire sprouting has not been documented, although stump-sprouting has been reported after mechanical removal [ 31 ]. Mature individuals were reported in forest communities of the Chisos Mountains of Texas which had burned at periodic intervals during the last 50 years [ 8 ].
This may indicate the presence of morphological adaptations which permit survival. Alternately, fuels may have been discontinuous or light and the burns patchy or of low severity. Vigorous stump-sprouting has been reported after mechanical removal [ 31 ], but postfire sprouting has not been reported. Since Texas madrone is relatively rare and fire uncommon in many communities in which it occurs, lack of published accounts may not necessarily rule out the possibility of postfire sprouting.
Seed is produced in abundance [ 26 ] and is widely dispersed by birds [ 19 ]. Very limited seedling establishment may occur on favorable sites. These relatively rare and fragile areas provide important food and cover for desert wildlife [ 21 ]. Because browse and cover are often limited in these areas, burning is not generally recommended [ 21 ].
Bernard, Stephen R. Note Department of the Interior, Bureau of Land Management. Bock, Carl E. In: Krammes, J. Fort Collins, CO: U. Brown, David E. Madrean evergreen woodland. In: Brown, David E. Desert Plants. Buechner, Helmut K. American Midland Naturalist. Cottle, H. Studies in the vegetation of southwestern Texas. Dayton, William A.
Important western browse plants. Washington, DC: U. Department of Agriculture. Denyes, H. Dick-Peddie, William A. Doganlar, M. Angew Entomol. Garrison, George A. Gehlbach, Frederick R. Hardesty, W. Texas madrone. Hastings, James R. Kartesz, John T. In: Kartesz, John T.
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SelecTree: Tree Detail
Arbutus Species, Naked Indian Tree, Texas Madrone