USVI Public Records

Document text

FOREST SERVICE RESEARCH PAPER ITF-17 JULY 1973 SEED SOURCE VARIATION IN PUERTO RICO AND VIRGIN ISLANDS GROWN MAHOGANIES BY T. F. GEARY, H, BARRES. AND R. YBARRA-CORONADO . “• ' : • V - ju ¿ 'ià INSTITUTE OF TROPICAL FORESTRY RIO PIEDRAS, PUERTO RICO FOREST SERVICE Fi ‘ • • I • 'i - V * ' • . I. — • r..-a -r- * ï.'.v. . * n * * "S U. S. DEPARTMENT OF AGRICULTURE SUMMARY Seeds were collected from natural stands of Swietenia macrophylla and in eighteen areas from Mexico through Panama and seedlings from the seeds were planted at thirteen locations in Puerto Rico and the Virgin Islands. Swietenia mahagoni from naturalized stands in the Virgin Islands were included in the plantings. Differences exist to varying degrees in seed pods, seedling characteristics, survival after field planting susceptibility to shoot borer attack, growth rate and leaf characteristics between species and among seed sources within species. Differences between species were more important than differences among seed sources in the important characteristic of adaptability as a timber species. Planting location was also very important. S. macrophylla is recommended for plantations in most of the Subtropical Moist and Wet Ecological Life Zones, but only on a small scale because of shoot borer and weed problems. The data suggest that native areas with the shortest dry season may be the best source of seed for S. macrophylla plantations in Puerto Rico. No mahogany is recommended for the coolest,, wettest portion of the Subtropical Wet Life Zone or the Subtropical Lower Montane Wet Zone. A hybrid, S. macrophylla x S. mahagoni, is the mahogany for planting for timber production in the Subtropical Dry and transitional area of the Subtropical Moist Zone. O.D.C.232.12:176.1 Swietenia: (729.5) RESUMEN Se escogieron semillas de Swietenia macrophylla y Swietenia hümilis de rodales naturales en 18 áreas desde México hasta Panamá, y las plántulas de estas semillas fueron plantadas en trece sitios en Puerto Rico y las Islas Vírgenes. En estas plantaciones se incluyó Swietenia mahagoni de rodales naturalizados en Islas Vírgenes. Hay diferencias, hasta cierto grado, en la forma de las bellotas, características de las plántulas, grado de supervivencia después de plantadas, susceptibilidad al ataque del barrenador, grado de crecimiento y características de la hoja, entre las especies y la procedencia de las semillas. Las diferencias entre especies resultaron más importantes que las diferencias entre procedencias, en su importante característica de adaptabilidad como especie maderable. También fué muy importante el sitio donde se plantaron. S. macrophylla es recomendada para la mayoría de las plantaciones en Zonas de Vida Ecológica Muy Húmeda y Húmeda Subtropical, pero solamente en pequeña escala, debido a los problemas causados por el barrenador y los yerbajos. Los datos adquiridos sugieren que las áreas nativas que tienen una temporada de sequía corta podrían ser la mejor procedencia para plantaciones de S. macrophylla en Puerto Rico. No se recomienda ninguna caoba para la parte más fresca y más húmeda de la Zona Muy Húmeda Subtropical o para la Zona Muy Húmeda Montano Bajo Subtropical. Para la producción de madera en la Zona Seca Subtropical y en el área transitoria de la Zona Húmeda Subtropical la híbrida, S. macrophylla x S. mahagoni es la caoba más apropiada a ser plantada. SEED SOURCE VARIATION IN PUERTO RICO AND VIRGIN ISLANDS GROWN MAHOGANIES by T. F. Geary, H. Barres, and R. Ybarra-Coronado Institute of Tropical Forestry, Rio Piedras, Puerto Rico^/ INTRODUCTION AND METHODS Seed was collected from natural stands of Honduras mahogany, Swietenia macrophylla King, and Pacific mahogany, Swietenia humilis Zucc., in eighteen areas from Mexico through Panama in 1964 and 1965 (Table 1, Figure 1). Mature seed pods were usually obtained by shooting them from the trees, and it was attempted to collect five pods from each of sixteen trees of normal appearance in each area. In collection HGA the seed had fallen and was collected from underneath the mother trees. The collection areas, mother trees, seed pods, and season of maximum seed ripeness are described in Appendixes I, II, and III. The seeds were obtained in two trips approximately one year apart and the resulting two seed collections were sown as separate experiments. The first trip covered the northern part of the collection area (all the Mexico seed sources and one of S. macrophylla from Guatemala) and the second trip covered the southern part. Seedlings were produced by directly sowing soil-filled polyethylene bags. The seedlings of each mother tree were grouped together in the nursery and the groups were distributed in random order in the beds. No measurements were made of the seedlings from the northern collection, but height, number of simple leaves, and presence or absence of compound leaves were recorded for the five tallest seedlings from each mother tree from the southern collection five months after sowing. Approximately seven-month seedlings of the nine seed sources from the northern collection were planted at eleven locations in Puerto Rico and two in St. Croix, U.S. Virgin Islands (Table 2). The locations are ranked in Table 2 in approximate order of decreasing temperature and increasing rainfall, so that Coamo is hot and very dry, and Guilarte cool and very wet. Added to the plantings, except at Estate Jealousy, were seedlings of West Indies mahogany, Swietenia mahagoni Jacquin, grown from seed collected in St. Croix, where this species has become naturalized. The initial plantings in St. Croix were destroyed by error and were replanted ten months later. The eleven locations in Puerto Rico were planted with approximately seven-month seedlings of the southern collection approximately a year after planting the northern seedlings. Usually the planting areas of the * two collections were side by side within locations, although occasionally they had to be separated because of terrain. For example, at Guajataca in the limestone hills of northwestern Puerto Rico, the two collections were planted at the bottom of different sink holes. The plantings of the southern collection included ten seed sources, but one has been excluded from the report because all of its seedlings came from a single mother tree. — In cooperation with the University of Puerto Rico 1 The planting design was the same at each location for each collection, and 2.4 meter square spacing was used throughout. The basic units were single tree plots arranged into 3 plot x 3 plot square blocks. Nine different seed sources were planted in each block. There were 32 blocks for each collection at each location and these were laid out in a 4 block x 8 block rectangle. It was attempted to plant the same number ol seedlings from each of 16 mother trees at each location. However, this was not possible because ot lack ol seedlings for some mother trees, less than 16 mother trees of sources MHA and MPA, and the 9 cell instead of a 10 cell block. There was a considerable difference among seed sources in the broadness of the genetic base (Table 3). At one extreme source HMB was represented in the eleven Puerto Rico field plantings by only 7 mother trees and there was large variation in the number of seedlings planted from each of the seven. One mother tree alone was the source of 46% of the HMB seedlings. At the other extreme the number of seedlings planted from each mother tree of source HSA only ranged from 20 to 24. The Puerto Rico locations except Coamo were planted within a period ot six weeks with the seedlings from the northern collection. Coamo was planted six weeks later than any other. All Puerto Rico locations were planted within a period of four weeks with the southern seedlings. Most of the plantings occurred in the months of November and December of 1964 and 1965. Seedlings that died within the first few months ol planting were replaced within eight months of the initial planting (or the complete replanting in St. Croix) and usually within four months. Five percent of the northern seedlings and six percent of the southern were replaced. Field measurements have been made a number of times since planting. Recorded were survival, height and diameter breast height (DBH), and whether or not trees were attacked by the mahogany shoot borer, Hypsipyla grandella Zeller, during the preceding year. In this report survival and growth are based on measurements made during late March-early April 1971 in Puerto Rico and mid-February, 1971, in St. Croix. The trees of northern origin were then in their seventh year of growth (sixth year in St. Croix) and the southern trees were in their sixth year. The report on shoot borer is based primarily on data recorded during February and March of 1969, when it was still possible to distinguish the tip of the leader. Measurements of leaf characteristics were also made in 1969 on a sub-sample of trees. The locations in Puerto Rico were stratified into three size classes based on height. From each stratum one location was selected at random, and at each location five sample trees of each seed source were randomly selected. From each tree one mature, undamaged leaf was selected from one of sixteen crown regions. Measured were lengths of petioles, rachises, leaflets, and petiolules; leaflet length; leaflet maximum width; and number of leaflets. Statistical analysis of field survival and growth posed a problem because of the non-orthogonal field design, replantings, missing plots, differences in measured growth intervals, heterogeneity of variances, and interactions. Therefore, for many comparisons, no statistical analyses of variance were made. Mean annual height increment was used for many comparisons to adjust for the differences in measurement periods. On subsets of data on which analyses of variance were made the following was done: for survival, transformation to arc sin values and two-way anova; for height and DBH, multiple regression analysis ignoring differences in length of the measurement periods; the five percent confidence level was chosen for establishing statistical significance. 2 RESULTS Seedling characteristics — southern collection The nine southern seed :sources; varied in seedling height, number of simple leaves and number of compound leaves (Table 4). The superior height of seed sources MNB and MNA was later to be found in the field plantings. Except for this, nursery heights did not predict future field results. The number of simple leaves on a seedling was independent of species and seedling height, and there was no obvious relationship to geographic origin. The average seed source of S. macrophylla has few seedlings with compound leaves after five months growth in the nursery and those of S. humilis had many. However, few seedlings of seed source HGA had compound leaves and this resemblance of HGA to typical S. macrophylla was found in subsequent field analyses. HCA showed an intermediate response in seedlings with compound leaves, as it often did later in other characteristics. Survival in field plantings A much greater percentage of S. macrophylla (M) trees survived than trees of S. humilis (H) and S. mahagoni (WIM) when averaged over all planting locations (Table 5.). However, there was a major interaction in species survival with moisture regime of the planting location. At the drier planting locations, survival of S. humilis and S. mahagoni was greater than that of S. macrophylla. This difference on the drier sites was statistically significant in the plantings of the southern collection only. There was no difference in survival between S. humilis and S. mahagoni. Within a species there was considerable variation in survival associated with seed source. On the wetter sites there were statistically significant differences among seed sources of S. macrophylla of both northern and southern collections, and among S. humilis seed sources of * tRe southern, but not northern collection. However, on drier locations the only significant difference among seed sources within a species was that of S. humilis seed sources of the northern collection. The most outstanding variation associated with seed source was that of seed source HGA which survived in a pattern more typical of S. macrophylla than S. humilis (i.e., percentage survival was greater on wetter than on drier locations), and that of HCA which survived equally well on both wet and dry locations. In addition to the distinction in survival between wetter and drier locations, there were significant differences in survival among locations within the two moisture classifications (Table 6). Very low survival occurred at Estate Jealousy, where there were maintenance problems in addition to drought; in the northern collection at Guilarte, where road building activity caused soil movement over some plots; in the southern collection at Coamo, where severe drought occurred during the establishment period; and among most seed sources of S. humilis and S. mahagoni on many of the wetter sites, especially at the three that were probably the coolest and wettest, Maricao, Matrullas, and Guilarte. There was no evidence that within the two moisture classifications the pattern of survival of any individual seed source from location to location differed from that of the overall species, including seed sources HGA and HCA. 3 Seven locations were selected for more intensive statistical analyses of survival on the basis of their lack of establishment problems, presence of both collections, and climatic suitability for mahogany culture. Seed sources of poor adaptability (S mahagoni and all but one seed source of S. humilis) at these locations were excluded. There were statistically significant differences in survival associated with seed source and planting location (Table 7). But in general suivival of all seed sources and at all planting locations was lair to good. There was little difference in survival between collections and there was a greater range in survival associated with planting locations than with seed source. Shoot borer attack As of January 1969, four and three years respectively after planting the northern and southern collections, shoot borer attacks were recorded at seven locations (Table 8). Unattacked were the two St. Croix locations, Guajataca, and the three coolest wettes locations in Puerto Rico. Very few trees were attacked at Rio Abajo, while attack was heavy at Cambalache, Tract 105, and El Verde. By early 1971 all but Guajataca and Maricao of the borer-free locations in early 1969 were being attacked, some of them heavily, and attack at Rio Abajo had become heavy, as shown below: Shoot borer attack in late 1970-early 1971 in previously unattacked locations Location JEAL THOM RABA MATR GUIL Trees attacked (%) 739671 2041 In contrast at Coamo, Las Marias, and Guavate, almost no new attacks were recorded in 1970 and 1971, while at Cambalache, Tract 105, and El Verde, borer attack continued heavily. Shoot borer attack at the various locations could be classified as follows: Extent of Shoot Borer Attack Problem Serious Minor None JEAL COAM GUAJ THOM LMAR MARI CAMB GUAV T105 MATR RABA GUIL EVER A greater percentage of S. macrophylla trees were attacked than S. humilis trees, and mahagoni showed no signs of attack (Table 8). There was no evidence of geographical variation in susceptibility to borer attack within 5. macrophylla. Within S. humilis HGA and HCA, again showing characteristics of S. macrophylla, were attacked more than other seed sources. 4 Growth in field plantings Height growth followed a pattern similar to survival. Trees of S. macrophylla grew more rapidly in height than trees of S. humilis and S. mahagoni (Table 9). Again there was an interaction with moisture regime of the planting location. Trees of S. macrophylla grew more rapidly on wetter sites than drier sites, while trees of S. humilis and S. mahagoni grew more rapidly on drier than wetter sites, but never more rapidly than trees of S. macrophylla (ignoring individual seed source variations). And again HGA and to some extent, HCA, exhibited characteristics typical of S. macrophylla. There was no difference in the rate of growth between S. humilis and S. mahagoni. Growth of S. macrophylla was poorest at the driest (COAM) and the three coolest, wettest locations (MART, MATR, GUIL), and of the remaining locations growth of S. macrophylla was best at the three (GUAJ, LMAR, GUAV) where shoot borer attack wasn’t a serious problem (Table 10). Statistical analysis of the six fastest growing seed sources (all S. macrophylla except for HGA) of each collection on the seven locations in Puerto Rico with the best growth revealed statistically significant differences associated with seed source and planting location (Table 11). The few months difference in the measured period of growth between locations was ignored for this analysis. Poorest growth in the northern collection was that of MMA and MME, although MME did relatively much better at the drier location (Table 9). The two southern most sources of S. macrophylla and the S. humilis source HGA grew poorest within the southern collection, although on drier sites they grew relatively better. S. macrophylla of the southern collection has grown faster than that of the northern collection, and seed sources MNB and MNA have grown outstandingly. At a moist site with only minor shoot borer attack (LMAR), these two seed sources grew at a rate of 1.75 meters a year. This superiority, however, did not occur on the drier sites. Best height growth occurred at the three locations (LMAR, GUAV, and GUAJ) with little or no borer attack. Although not analyzed statistically growth was also good at the two St. Croix locations (1.0 m/yr.). DBH growth fitted in the pattern of height growth with the exception of the northern collection at El Verde, where DBH growth was relatively better than height, no doubt reflecting the greater impact of shoot borer on height. Leaf dimensions The leaves of S. macrophylla trees had more leaflets and were larger than those of S. humilis, which in turn were greater than those of S. mahagoni (Table 12). The numbers and sizes varied with seed source within a species, but there were no obvious geographical patterns nor important differences except for seed source HGA and to a lesser extent HCA. These exhibited characteristics typical of S. macrophylla instead of S. humilis. Planting location had a greater effect on petiole and rachis length than seed source. For example, location variance accounted for 28% of the total variance in petiole length as opposed to 9% for seed source variance. However, the total length of the main leaf axis (petiole plus rachis) varied little from location to location, nor did leaflet number and leaflet dimensions. 5 DISCUSSION Differences exist among seed sources of Swie tenia in seed pods (Appendix III), seedling characteristics (Table 4). survival after field planting (Table 5), susceptibility to shoot borer attack (Table 8), growth rate (Table 9), and leaf characteristics (Table 1_). These differences could not be related to a geographical pattern, although superficial examination might suggest one. For example, the northernmost seed source of S. M M A, survived and grew least of all the 5. macrophylla seed sources. However, in addition to being the northernmost, it was also the one with the greatest variation in plantable seedlings produced per mother tree (Table 3), and the seed was collected in an area where considerable dysgenic selection apparently had occurred (Appendix I). The greatest practical differences were those between species and those caused by planting location, the latter in turn influenced by shoot borer attack. S. macrophylla has grown faster than S. humilis and S. mahagoni on all types of sites, although the latter two are more drought resistant. S. macrophylla then is the species ot choice for planting within most of the Subtropical Moist and Wet Ecological Life Zones of Puerto Rico. In Subtropical Dry and in the transitional area of the Subtropical Moist Zone, the hybr'd, macrophylla x S. mahagoni should be planted (Geary, Nobles, and Briscoe, 1972). t as yet to be shown by experimentation whether the hybrid should also be preferred in wet or zones. Mahoganies do not seem adapted to the Subtropical Lower Montane Wet Zone or the wettest part of the Subtropical Wet Zone, nor to serpentine soils, the soil type ot the Maricao location. Shoot borer had a great impact on mahogany growth. It seems certain that the mahoganies at Tract 105, El Verde, Cambalache, and Rio Abajo would have been much taller if they had not been attacked. The lack of attack at some locations is difficult to explain. Shade on the trees reportedly protects against attack (Marshall, 1939; Tropical Forest Experiment Station, 1953; Grijpma and Gara, 1970), and the mahoganies at Las Marias, Guavate, and Guajataca did have some shade from surrounding forest and poisoned overstory trees, while those at El Verde, Cambalache, and Rio Abajo were in open fields. However, trees at Tract 105 also had some shade on them. Nevertheless from past experience with mahogany culture it seems safe to conclude that the trees at El Verde, Cambalache, and Rio Abajo were severely attacked because they were in open fields. The low incidence of attack at Matrullas, Guilarte, and Maricao, • the cessation of attack at Coamo, and the lower attack incidence of S. humilis certainly were partially related to poorer tree growth, since the moth stage of the borer is attracted to fresh foliage (Grijpma and Gara, 1970). Climatic effects on borer activity as well as some shade may also have contributed to the lower incidence at the coolest, wettest locations. Tree growth at Estates Thomas and Jealousy did not seem affected by shoot borer only because these attacks did not occur until after a period of initial very rapid height growth. In the years to come the effect should become more evident. The reason for the delayed attack at Estates Thomas and Jealousy, where the plantings are in open fields, no doubt was caused by adverse climatological factors and initially low levels of shoot borer population. Only S. mahagoni of all the seed sources studied showed immunity to attack. 6 If S. macrophylla is to be planted, then where should the seed come from? Selection of collection area based on climate as a criterion might be rational. There was an obvious interaction of seed source with moisture regime of the planting locations and this can be more or less related to the length of the dry season (Appendix I) of the seed collection areas. The fastest growing seed sources (MNA and MNB) at moist and wet locations originated in the areas with the shortest dry season, and the two poorest growers at the same locations were from areas with the longest dry season. At the drier locations this superiority of MNA and MNB did not exist. S. humilis seed source, HGA, came from an area with the shortest dry season for this species, and this might explain its better growth. However, there are obstacles to completely accepting this argument. Firstly, seed sources MMA and MME came from areas with a lot of dysgenic selection. Secondly, on the drier sites shoot borer attack may have tended to keep all seed sources at uniform height by killing back new shoots of all lengths. Thirdly, records were not kept of seedling yield from seed sown, or the percentage of seedlings used. It is possible that at least some of the seed source variation could be due to different selection intensities within the nursery (Geary and Barros, 1973). Probably the most important question is whether mahogany plantations should be established. Experience has shown that weeds are a serious problem in mahogany culture in Puerto Rico and are expensive to control. Mahoganies maintain a narrow crown for many years, thus not suppressing weeds; and in moist and wet zones on fertile sites, vines are continuously suppressing the trees. On well cleaned sites, shoot borers often ruin the tree form and reduce growth. Therefore, we do not recommend mahogany plantations be established on a large scale in Subtropical Moist and Wet Zones. Individual landowners may be willing to do the required weeding effort with small plantations on nutrient rich sites to grow this fine quality -cabinet wood. In the Subtropical Dry Life Zone and • into the transitional area of the Subtropical Moist, planting of hybrid mahoganies has been recommended, mainly because it is for all practical purposes the only timber tree that can be recommended. Growers in the drier areas can keep brush around young trees to cast shade on the crowns to reduce borer attack and later when crowns emerge into full light, prune to single leaders following shoot borer attack. In moist and wet zones, landowners have a choice of pines, eucalypts, and teak, among other species, that are easier and cheaper to grow. Priority research on mahoganies in Puerto Rico and the Virgin Islands should be on improving cultural techniques to reduce weeding costs, controlling shoot borer, and trying the hybrid in the moist and wet zones. More genecology would have lesser priority. ACKNOWLEDGMENTS We thank the following for their support: Harvlan, Inc. for land at Estate Jealousy; Mr. Jaime Ensenat for land in Las Marias; Mr. José Ismael Zayas for land in Coamo; the Puerto Rico Office of Conservation of Forest Resources for land in the Cambalache, Guajataca, Rio Abajo, Guavate, Maricao, Toro Negro (Matrullas), and Guilarte State Forests, and Mr. M. Antoni of the University of Puerto Rico, Agricultural Experiment Station for statistical assistance. 7 LITERATURE CITED (1) Geary, T. F. and de Barros, N. F. 1973. Seed crop environment may influence progeny tests. Commonwealth Forestry Review 52: (in press). (2) Geary, T. F., Nobles, R. W., and Briscoe, C. B. 1972. Hybrid mahogany recommended for planting in the Virgin Islands. USD A Forest Service Research Paper ITF-15. (3) Grijpma, P. and Gara, R. I. 1970. Studies on the shoot borer Hypsipyla grandella Zeller. I. Host selection behavior. Turrialba 20:233-240. (4) Holdridge, L. R. 1967. Life zone ecology. Tropical Science Center, San José, Costa Rica. 206p. (5) Marshall, R. C. 1939. Silviculture of the trees of Trinidad and Tobago. Oxford Univ. Press, London. 240 p. (6) Tropical Forest Experiment Station 1953. Thirteenth annual report, Carib. Forester 14(1&2):13. 8 Honduras Costa Rica Figure 1. Seed collection areas in Mexico and Central America, codes as in Table 1. Table 3.— Variation in number of seedlings planted for seed sources and mother trees. Seedlings Coefficient of « / Seed Mother trees in planted^/ variation^.' Source plantings (no.) (no.) (%) MMA 12 263 137 MMB 16 350 33 MMC 14 367 80 MMD 16 343 34 MME 16 361 10 MGA 16 347 17 MHA 7 254 99 MNA 16 350 14 MNB 16 335 43 MPA 15 349 7 MPB 16 351 12 HMA 14 357 80 HMB 7 156 123 HME 16 337 9 HGA 15 351 19 HSA 16 352 6 HNA 16 351 9 HCA 16 348 20 a/ Initial field planting, i.e., excludes replacements. b/ Standard deviation of number of seedlings planted from each mother tree, times 100, and divided by the average number of seedlings planted per mother tree. Seed Source Simple leaves per tree (no. )ü/ Seedlings with compound leaves MHA 19.5 MNA 24.8 MNB 24.8 MPA 20.0 MPB 18.0 HGA 21.3 HSA 21.4 HNA 20.4 HCA 20.8 8.4 0.6 11.0 0.4 10.7 0.7 11.1 1.9 9.8 2.2 9.8 0.8 6.6 5.0 6.9 5.0 10.8 3.0 a/ Mean of five tallest seedlings from each mother tree Table 5 — Survival of Su)i.zte.nC a seed sources in Puerto Rico and the Virgin Islands as influenced by moisture regime of the planting location. I Northern collection Southern collection Seed All 13 9 wetter 4 drier Seed All 11 9 wetter 2 drier source locations locations locations source locations locations locations % survival % survival MMA 65 73 48 MHA 82 89 50 MMB 72 80 53 MNA 80 88 40 MMC 64 71 48 MNB 76 87 26 MMD 72 77 60 MPA 66 72 37 MME 73 77 64 MPB 21 78 52 MGA 75 81 63 M mean 75 83 41 M mean 70 76 56 HGA 80 85 58 HMA 38 26 64 HSA 47 41 74 HMB 38 28 60 HNA 46 38 80 HME 41 27 74 HCA 21 71 77 H mean 39 27 69 H mean 61 59 72 WIM 35 23 68 Table 6.— Variation in survival of SlvZ eX & nia species from location to location in Puerto Rico and the Virgin Islands-] Northern collection Southern collection Moisture regime Location MCLCAOpkifttCL hum CLó> Mahagoni____magnophytfaa_____hcuniLCò % survival Drier Wetter COAM 52 JEAL 18 THOM 84 CAMB 70 GUAJ 76 T105 85 LMAR 71 RABA 70 EVER 88 GUAV 92 MARI 78 MATR 72 GUIL 56 76 84 26 • • 91 89 71 70 34 17 18 8 29 27 41 43 79 59 26 26 9 14 0 4 5 8 16 • • 52 • • • • 66 • • 92 87 84 87 48 73 77 93 82 91 90 88 62 68 18 72 33 87 37 Table 7.— Statistically significant differences in survival among selecF~StOx.eX&ma seed sources and planting locations. Variation among seed sources Northern collection Southern collection Seed Survival Seed Survival source % source 7« MGA 84 ia / HGA 931 MMD 82 MPB 89 MME 82 MHA 88 MMB 80 MNA 85 MMA 72 MNB 81 MMC 72 MPA 75 Variation among planting locations Northern collection Southern collection Planting Survival Planting Survival location % location Zo GUAV 92 RABA 93 EVER 88 EVER 92 T105 85 GUAJ 88 GUAJ 76 GUAV 88 LMAR 71 T105 88 CAMB 70 LMAR 76 RABA 70 CAMB 70 a/ — Values not connected by a at the 5% confidence level line are statistically different Table 8.— Shoot borer attack in field plantings in early 19.61. Planting location Trees attacked (%) Northern collection Southern collection Seed source Trees attacked (%)a / Seed source Trees attacked (%)a/ COAM 34 MMA 66 MHA 64 JEAL 0 MMB 68 MNA 64 THOM 0 MMC 63 MNB 73 CAMB 91 MMD 65 MPA 60 GUAJ 0 MME 64 MPB 59 T105 74 MGA 64 M mean 64 LMAR 28 M mean 65 RABA 2 HGA 65 r*» /a EVER 95 HMA 56 HSA 52 GUAV 37 HMB 42 HNA 45 MARI 0 HME 46 HCA 64 MATR 0 H mean 48 H mean 56 GUIL 0 WIM 0 — k t the six locations with most attack Table 9.— Annual height growth of five-to-six year old SwleXzrUxi seed sources in Puerto Rico and the Virgin Islands as influenced by moisture regime ol tne planting location. Northern collection Southern collection Seed source All 13 locations 9 wetter locations 4 drier locations Seed source All 11 locations 9 wetter locations 2 drier locations meters/year meters/year MMA 0.79 0.82 0.74 MHA 1.00 1.05 0.78 MMB 0.88 0.94 0.77 MNA 1.05 1.13 0.70 MMC 0.87 0.89 0.83 MNB 1.14 1.24 0.66 MMD 0.88 0.89 0.86 MPA 0.82 0.83 0.74 MHE 0.84 0.83 0.88 MPB 0.81 0.81 0.82 MGA 0.90 0.93 0.84 M mean 0.96 1.01 0.74 M mean 0.86 0.88 0.82 HGA 0.78 0.80 0.68 HMA 0.47 0.34 0.78 HSA 0.36 0.31 0.55 HMB 0.44 0.31 0.75 HNA 0.40 0.36 0.58 HME 0.40 0.23 0.77 HCA 0.62 0.60 0.67 H mean 0.44 0.30 0.76 H mean 0.54 0.52 0.62 WIM 0.45 0.34 0.71 Table 10.— Annual height growth of Sw^eX&Vlia. species on Puerto Rico and Virgin Islands planting locations Planting SlA)X.&£(Li/VLCL SlAlL&t(LVlL& location vmcAopkytta. kumoUA makagovU COAM 0.48 JEAL 1.04 THOM 0.96 CAMB 0.89 GUAJ 1.33 T105 1.01 LMAR 1.41 RABA 0.81 EVER 0.82 GUAV 1.27 MARI 0.67 MATR 0.53 GUIL 0.63 meters/year 0.41 0.44 0.96 • • • • 0.88 0.79 0.82 0.58 0.47 0.18 0.40 0.22 0.73 0.25 0.62 0.35 0.52 0.56 0.52 0.56 0.13 0.21 0.17 0.29 0.28 0.46 Table 11.— Height of the fastest growing five-to-six-years-old seed sources of SW-Ltte.ru.QL on the best sites in Puerto Rico. Comparison Northern seed sources^.a/ Southern seed sources—b/ Locations over northern sources^a/ Locations over southern sources^b/ Height growth DBH growth Seed source Height Seed source DBH or location (meters) or location (cm) MMB 6.6 sJ MMB 8.2 MGA 6.6 MGA 7.4 MMD 6.4 MMC 7.3 MMC 6.3 MMD 7.2 MME 6.1 MMA 6.8 MMA 5.7 MME 6.6 MNB 7.4 MNB 7.1 MNA 6.9 MNA 6.8 MHA 6.3 MHA 6.8 MPB 5.5 HGA 6.7 HGA 5.4 MPA 5.6 MPA 5.3 MPB 5.5 LMAR 8.0 GUAV 8.5 GUAV 7.9 LMAR 8.3 GUAJ 7.3 EVER 7.6 T105 5.9 T105 7.0 EVER 5.2 GUAJ 6.8 CAMB 5.1 CAMB 6.7 RABA 4.6 RABA 5.9 LMAR 8.6 LMAR 8.7 GUAJ 7.8 GUAJ 6.6 GUAV 6.6 GUAV 6.6 T105 5.5 CAMB 6.3 CAMB 5.4 RABA 6.1 RABA 5.0 T105 5.4 EVER 4.0 EVER 5.3 a/ Approximately six years after planting. b/ Approximately five years after planting. £,/ Values not connected by a line are statistically different at the 5/ confidence level. Table 12.— Leaflet numbers and leaf dimensions of Swfc&tenta seed sources. Seed source Leaflets (no.) Petiole length(cm) Rachis length(cm) Petiolule length(cm) Leaflet length(cm) Leaflet width(cm) MMA 11.3 14 30 0.52 19 6.5 MMB 12.4 20 31 0.62 20 7.3 MMC 11.0 20 29 0.70 19 7.1 MMD 11.4 15 24 0.50 17 5.9 MME 10.8 15 24 0.48 16 6.1 MGA 11.3 19 21 0.56 17 6.1 MHA 10.5 18 26 0.52 19 6.6 MNA 11.1 18 27 0.42 17 5.8 MNB 10.3 16 27 0.52 19 6.5 MPA 9.4 14 22 0.58 15 5.9 MPB 11.3 19 24 0.61 15 6.1 M mean 11.0 17 26 0.55 18 6.3 HMA 9.8 11 16 0.27 10 4.2 HMB 9.3 11 16 0.10 11 4.6 HME 10.4 10 14 0.19 10 4.0 HGA 10.5 20 28 0.80 18 6.8 HNA 9.9 12 17 0.24 11 4.2 HSA 9.4 13 13 0.16 11 4.2 HCA 12.1 11 23 0.29 13 5.0 H mean 10.2 13 18 0.29 12 4.7 WIM 9.7 5 8 0.27 5 2.1 T - a/ Location— GUAJ 11.4 12 26 0.46 15 5.8 LMAR 11.2 21 18 0.47 16 5. 5 MARI 9.4 13 30 0.42 18 5.8 S. mahagoyit (WIM) excluded. Appendix I.— Description of the collection areas Dry Season Extent of remaining mahogany— ' Seed Source from to Months (No.) Altitude (meters) Topography Exploitation MMA Nov. May 7 25 Flat Some to muchi./ NN MMB Jan. May 5 90 Flat None evident M MMC Feb. April 3 640 Mountainous^./ None evident VH MMD Dec. May 6 110 Flat Some M MME Sept. and May Jan. June 7 30 Flat Twice cut to diameter limit M MCA Feb. May 4 120 to 300 Hilly none evident H MHA April June 3 35 Mountainous^-/ None evident L MNA mid Feb. mid April 2 0 to 30 Flat None evident M MNB March April 2 15 Flat Some to much M MPA mid Dec. April 4 1/2 380 to 710 Mountainous^./ None to evident M MPB Jan. mid April 3 1/2 60 Hilly— / None to evident Mi/ HMA Dec. May 6 150 to 210 Hillyb/ None to evident NN HMB Nov. June 8 30 to 90 Mountainous^./— / None to evident NN MHE April Sept. 6 180 to 210 Hilly— / Much NN HGA Dec. April 5 45 Flat Some L HSA Nov. April 6 460 to 610 Hilly— / Much NN HNA Nov. 4pril 6 150 Hilly Much NN HCA Nov. May 7 90 Flat Much NN a/ Trees found at bottom of slopes, b/ Trees found on slopes. c/ Collection trees foun<3 in 0.5 acre area left after logging, d/ VH= very heavy, H= heavy, M= medium, L= light, NN= next to none. el In the Chucunaque Indian Reservation; NN outside the reservation. Appendix II.— Description of the mother trees Seed source Height (meters) Diameter breast height (cm) Height to first branch (m) Height of buttresses (m) Mean Range Mean Range► MMA 21 15 — 23 55 35 — 90 9 0.8 MMB 20 12 — 26 55 20 — 85 8 0.6 MMC 49 35 — 57 180 130 — 260 20 2.1 MMD 22 14 — 30 80 60 — 140 10 0.9 MME 19 15 — 24 70 40 — 145 10 0.8 MGA 30 26 — 39 90 55 — 115 15 1.3 MHA 40 34 — 52 110 75 — 130 19 2.0 MNA 39 34 — 44 75 50 — 130 17 1.2 MNB 30 24 — 34 65 55 — 80 15 1.4 MPA 31 24 — 40 90 65 — 130 17 1.2 MPB 30 24 — 37 130 55 — 200 16 2.6 HMA 12 8 — 16 45 25 — 90 4 0.0 HMB 11 6 — 15 35 15 — 60 3 0.0 HME 9 8 — 14 35 20 — 85 3 0.0 HGA 16 11 — 22 65 25 — 100 8 0.5 HSA 9 8 — 11 20 15 — 30 3 0.0 HNA 10 8 — 14 r -O 15 — 60 3 0.0 HCA 14 9 19 55 25 100 4 0.3 Appendix III.— Description of the seed pods and months of maximum seed ripeness. Seed source MMA Pods measured Length (cm) Diameter (cm) (No.) 64 14.1 9.2 Rates of length to Months of maximum diameter seed ripeness 1.55 February MMB 64 15.5 10.0 1.55 February MMC 64 14.6 8.6 1.70 February MMD 64 12.6 8.2 1.55 February MME 64 12.6 8.5 1.50 February MGA 64 14.2 8.9 1.60 late Feb., mid March MHA 8 14.0 7.6 1.85 early February MNA 62 13.7 7.9 1.75 February MNB 58 13.0 7.5 1.75 February MPA 51 14.1 8.2 1.70 December MPB 58 14.8 8.9 1.65 mid November HMA 64 11.8 7.9 1.50 late January HMB 63 14.0 9.0 1.55 February HME 42 12.6 9.4 1.35 late Dec., Jan. HGA 0 • • • • • • • • • January HSA 53 13.3 8.7 1.55 early February HNA 42 13.4 9.6 1.40 January HCA 55 12.8 8.6 1.50 mid Jan., early Feb.