6.0 m by 7.2 m in January 1964. Slash pine seedlings were half-
siblings (from the same mother tree), but the loblolly seedlings
were run-of-nursery stock. In May 1964 survival of loblolly
pine was 100 % in all plots; whereas survival of slash pine varied
from 85% to 92%-with the best survival in plots with the
water table maintained at 46 cm. At this time, all dead slash
pine seedlings in the inside (measurement) rows were replaced
by living trees taken from the outside or border rows with a
transplanting bucket. Missing trees in the border rows were
replaced by fresh nursery stock.
 Annual measurements of total tree height and groundline
diameter (outside bark) were recorded on all trees of the middle
three rows of each treatment plot at the end of each growing
season. However, only those measurements made at the end of
the fifth year are presented herein. Soil samples were collected
from the 0-10, 10-20, and 20-30 cm depth, with a 2.5 cm diameter
tube from each fertilizer and water table treatment plot in the
loblolly pine series, at the conclusion of the experiment. Each
sample was a composite of 12 cores taken from the center of
the rows. They were used for the determination of residual
total P.

Biomass Sampling
 After five growing seasons, three trees on each plot-a small,
medium, and large tree, to represent the range of diameters and
heights present-were selected from the measurement rows for
stem analysis and total tree sampling. During January 1969
each sample tree was felled at groundline. Total tree heights
were measured by tape to nearest centimeter, and diameters
(outside bark) were measured at groundline by diameter tape
and recorded to nearest tenth of centimeter for each tree. All
foliage and branches were collected separately. The boles were
cut into 1.2 m sections, and the diameters inside and outside
bark at the butt and top of each section were measured and
recorded.
 Only slash pine roots were sampled. A tractor-mounted
backhoe was used to trench around each tree stump on three
sides, and the large root system was excavated using water
under high pressure from a fire hose and nozzle. The hose was
connected to an irrigation system for a continuous water supply
at approximately 60 psi pressure.
 Fine root biomass in the top 15 cm of soil was estimated on
an area basis by sampling as follows. Two 0.184 square meter