trees in plots with fluctuating and 46- and 92-cm water tables
were 25.3%, 10.6%, and 6.0% for slash pine and 26.9%, 18.4%,
and 9.5% for loblolly pine.
 The greatest increase in height growth was related to water
 table depth rather than to fertilization. Maximum growth oc-
 curred on the 46-cm water table (Figure 1, Tables 1, 2). The
 percentage increases in height of trees on the 46- and 92-cm
 water tables over trees on the fluctuating water tables were
 44% and 35% for slash and 75% and 38% for loblolly.
 The loblolly pine response was impaired by serious tip moth
 attack during the second and third years after planting. Slash
 pine was little affected by this insect.

 Biomass
 Tree diameters and heights ayexclosely_ correlated, and they
 are both good estimators of the rights of tree part (Table 3).
 The formula, logarithm dry weight = Bo+B1 (logarithm
 groundline diameter) + B2 (logarithm tree height), was used
/ to estimathethe weights of the uncut trees i the plots. Diameter
Sgroundline (outside bark) was used in place of diameter breast
high because some trees were less than 1.4 meters tall. The
constants, regression coefficients, correlation coefficients, and

 Table 1.-Summary of the mensurational survey of fertilized and non-
 fertilized 5-year-old slash and loblolly pines growing on three water table
 treatments.
 Treatments
 Species Fertilizeda Water Tableb Height Diametere Volumed Stems
 cm m cm cu m/ha no./ha
Slash No Fluctuating 3.24 7.4 28.4 7623
Slash Yes Fluctuating 4.06 8.9 50.4 7623
Slash No 46 4.99 9.9 72.8 7175
Slash Yes 46 5.52 10.6 115.0 8072
Slash No 92 4.70 9.8 66.5 7175
Slash Yes 92 4.98 9.7 72.1 8072
Loblolly No Fluctuating 1.97 4.5 6.3 6726
Loblolly Yes Fluctuating 2.50 4.9 9.8 5830
Loblolly No 46 3.58 8.0 38.0 7175
Loblolly Yes 46 4.24 8.7 49.6 7175
Loblolly No 92 2.95 6.9 24.4 7623
Loblolly Yes 92 3.23 7.1 25.2 7175
aFertilized at beginning of second year with 392 kg/ha of diammonium phos-
 phate.
 bDepth from surface to water table where controlled.
 eDiameter outside bark at groundline.
 dCalculated by stem analysis.