The development of radiata pine (Pinus radiata D. Don.) clones was compared in
monoclonal and clonal mixture plots planted in an experiment established at Dalethorpe,
Canterbury, New Zealand with ten radiata pine clones in September 1993. Clones were
deployed in a randomised complete block plot design with three replications. Each
replication contained ten treatments of monoclonal plots and one in which all the clones
were intimately mixed in equal proportions.
Clones significantly differed in initial morphologies, survival and stem slenderness.
Sturdiness and initial heights were found to be the best predictors of initial survivals. The
study revealed that mode of deployment did not affect overall productivity, but individual
clones exhibited significantly different productivities between modes of deployment. All
clones contributed similarly to overall productivity in the monoclonal mode of deployment,
whereas the contribution of clones in the clonal mixture mode of deployment was
disproportionate. A minority of the clones contributed a majority of overall productivity in
the clonal mixture mode of deployment.
The inclusion of competition index as an independent variable in a distance-dependent
individual tree diameter increment model explained a significant amount of variability in
diameter growth. The use of an inverse-squared distance to neighbouring plants in the
competition index provided a slightly superior fit to the data compared to one that
employed a simple inverse of distance. Addition of genotype information in the
competition index further improved the fit of the model. Clones experienced different
levels of competition in monoclonal and clonal mixture modes of deployment. Competition
in monoclonal plots remained uniform over time, whereas some clones experienced greater
competition in clonal mixture plots which led to greater variability in their tree sizes. This
study indicated that single tree plot progeny test selections and early selections may miss
out some good genotypes that can grow rapidly if deployed monoclonally.
Stand level modelling revealed that clones differed significantly in modeled yield patterns
and model asymptotes. Clones formed two distinct groups having significantly different
yield models. The study also demonstrated that models developed from an initial few
years’ data were biased indicators of their relative future performances.
Evaluation of effectiveness of the 3-PG hybrid model using parameter values obtained
from destructive sampling and species-specific values from different studies revealed that
it is possible to calibrate this model for simulating the productivity of clones, and
predictions from this model might inform clonal selections at different sites under differing
climatic conditions. Destructive sampling at age 5 years revealed that clones significantly
differed in foliage and stem biomass. The differences in productivities of clones were
mainly due to differences in biomass partitioning and specific leaf areas.
Clones significantly differed in dynamic wood stiffness, stem-slenderness, branch
diameter, branch index and branch angle at an initial stocking of 1250 stems/ha. Mode of
deployment affected stem slenderness, which is sometimes related to stiffness. Although
dynamic stiffness was correlated with stem slenderness and stem slenderness exhibited a
significant influence on stiffness, clones did not exhibit statistically significant differences
in dynamic stiffness. Increasing initial stocking from 833 stems/ha to 2500 stems/ha
resulted in a 56 % decrease in branch diameter and a 17 % increase in branch angle.
Trees in the monoclonal mode of deployment exhibited greater uniformity with respect to
tree size, stem-slenderness, and competition experienced by clones compared to those in
the clonal mixture mode of deployment. Susceptibility of one clone to Woolly aphid
suggested that greater risks were associated with large scale deployment of susceptible
clones in a monoclonal mode of deployment.
This study also indicated that if the plants were to be deployed in a monoclonal mode then
block plot selections would have greater potential to enhance productivity.
| Identifer | oai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/1577 |
| Date | January 2008 |
| Creators | Sharma, Rajesh kumar |
| Publisher | University of Canterbury. School of Forestry |
| Source Sets | University of Canterbury |
| Language | English |
| Detected Language | English |
| Type | Electronic thesis or dissertation, Text |
| Rights | Copyright Rajesh kumar Sharma, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml |
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