Height growth of mahogany seedlings, St. Croix, Virgin Islands
Historic, arcliived document Do not assume content reflects current scientific l<nowledge, policies, or practices ~' T To-n SPe/tmce FOREST SERVICE - INSTITUTE OF TROPICAL FORESTRY '^'^H\0 PIEDRAS, i^UERTO RfGO U.S DEPARTMENT OF AGRICULTURE }??? December 1966 HEIGHT GROWTH OF MAHOGANY SEEDLINGS, ST. CROIX, VIRGIN ISLANDS, / By R. W. Nobles, and C. B Briscoe Summary AUG rZ 1957 CURRLNT SERlf-UECOROS Small-leaf mahogany seedlings grew more rapidly than bigleaf and their hybrids grew more rapidly than either for the first two years. However, by age 4 and conti- nuing through age 7, both hybrids and bigleaf were significantly taller than small-leaf. Bigleaf suffered the most mortality, followed by small- leaf, then the two hybrids. Re sum en Los estudios de crecimiento de caoba en Santa Cruz, Islas VIrgenes, indicaron que durante los primeros dos anos los hibridos de la caoba de hoja grande y de la caoba de hoja pequena sobrepasaron la caoba de hoja pequena, que a su vez sobrepaso la de hoja grande. …
Download the original document · Plain text (TXT) · Browse the archive · How this archive works
Original source: https://archive.org/download/heightgrowthofma10nobl/heightgrowthofma10nobl.pdf
SHA-256 3a0c410545a8feb044bab5e7cc1eb5311834fe6926ab16d455d7185bbbd0e451
Re-using this document
mixed and recorded per item: public domain by age or as a US government work for what was taken; controlled-digital-lending and restrictively licensed items EXCLUDED, each listed with its reason
Our description, tagging, arrangement, extracted text and machine transcripts are released under CC0 1.0. We assert nothing about the document itself.
Archive identifier LF-3a0c410545a8
Document text
Historic, arcliived document Do not assume content reflects current scientific l<nowledge, policies, or practices ~' T To-n SPe/tmce FOREST SERVICE - INSTITUTE OF TROPICAL FORESTRY '^'^H\0 PIEDRAS, i^UERTO RfGO U.S DEPARTMENT OF AGRICULTURE }??? December 1966 HEIGHT GROWTH OF MAHOGANY SEEDLINGS, ST. CROIX, VIRGIN ISLANDS, / By R. W. Nobles, and C. B Briscoe Summary AUG rZ 1957 CURRLNT SERlf-UECOROS Small-leaf mahogany seedlings grew more rapidly than bigleaf and their hybrids grew more rapidly than either for the first two years. However, by age 4 and conti- nuing through age 7, both hybrids and bigleaf were significantly taller than small-leaf. Bigleaf suffered the most mortality, followed by small- leaf, then the two hybrids. Re sum en Los estudios de crecimiento de caoba en Santa Cruz, Islas VIrgenes, indicaron que durante los primeros dos anos los hibridos de la caoba de hoja grande y de la caoba de hoja pequena sobrepasaron la caoba de hoja pequena, que a su vez sobrepaso la de hoja grande. Desde los 4 hasta los- 7 anos, la altura alcanzada por la caoba de hoja grande y por el hibrido de los arboles portagranos de las dos especies fue esencialmente igual, y todos sobrepasaron en altura a la caoba de hoja pequena. La caoba de hoja grande sufrio la mortalidad mayor seguida por la caoba de hoja pequena y finalmente por los dos hibridos * In cooperation with the University of Puerto Rico i/ Since the recognition of natural hybridization of small-leaf (West Indies) mahogany ( Swieten ia mahagoni Jacq.) v.'ith bigleaf (Honduras) mahogany (S. macrophy 1 la King) there has been con- jecture about their relative growth rates. One would expect small-leaf to be the fastest growing on dry sites, the hybrids to be fastest on intermediate sites, and bigleaf to excel on wet sites. In 1960 a comparison was begu on St. Croix, Virgin Islands, were planted: Seedl ing Bigleaf Medium leaf Mediumleaf Smal 1- leaf on dry and intermediate sites Four types of 1-0 seedlings Mother-tree Bigleaf Bigleaf Sma 1 1 - leaf Sma 1 1 - leaf Each plot contained one seedling of each type, a total of 4, at 3-meter (10-foot) spacing. There were 9 well-scattered plots at each of 11 locations. Elevations range up to 180 meters (600 feet) above sea level. Mean annual rainfall varies from 700 to 1400 mm (29 to 54 inches) per year for the 7 locations. Results from 7 locations are given in Table 1. The remaining locations were eliminated: three because of drouth mortality and one because of destruction by bulldozer. For the first two years: (a) Both types of hybrid seedlings outgrew both species - at all locations but one, where small-leaf grew slightly more— . (b) Small-leaf growth exceeded bigleaf growth. (c) The hybrids were not different from each other. After 7 years, both hybrids average 15 centimeters (6 inches) taller than the bigleaf, but the difference is not significant. The bigleaf averages 1.5 meters (5 feet) taller than small-leaf, a highly significant difference. y C. B, Briscoe and F. B. Lamb. 1962, Leaf size in Swietenia . Car. For. 23:2:112-115. y C. B. Briscoe and R. W. Nobles. 1962. Height growth of mahogany seedlings. Trop. For. Notes #13. 2 Because of prolonged dry spells, mortality in 7 years was high: 109 of 252 trees in all plots. In two of the wettest sites, Ham Bluff and Cane Bay, mortality jumped 44 percent and 36 percent, respectively, in the past 5 years. As expected, mortality was highest for bigleaf, 63 percent for all sites. Somewhat surprisingly, mortality for hybrids was less than for small-leaf, 37 and 32 percent compared to 44 percent. The present pattern of development was established by age 4, and has remained constant since, Table 1. 3 o -i P no3 cn X n CO CD O CU PJ fD l-'• -—N n D- 3 3 ri- O t—' O (D C/) 3 0^ Cr 3 h- DC' X OH- C &i C_, H- I 3 H-i t-hX ft) t-- 2 ft) o ?r W 0~1 tsj t—' t— o o o o o o o o o o o o o c; O CT> O Ji. Cn <3N OJ 00 CT\ 0^ • •••••••• H-'OOUlCT^UJt-nt—'I—'00 I~vJ-~jOOCJ^OO-vjvjji, OJ Cn t—' -sj >—' I—' 00 tsj oo &2 o > Tats H- 3 O i-h X W H- 3 t—' 5D r+ a> 70 i-h CD H- (JQ 3. t—' CD o o- P M Hi C3 3o rt fu 3- hh cn 3P ' 2 I—" CD I Cl I—' H c ru 3 3 P O i-h r+» 3^ (D cn 3P p ft> O O fD P 3 H- r+ H' P r+ P cr