Agroforestry Research in Ontario
Researcher: Mr. C. Nanni, Principal Researcher, Dr. C.S. Baldwin and Mr. B. Doidge, RCAT. Cooperating with Ministry of Natural Resources, Orono Nursery, Central Region, Orono
Intercropping - Initial tree establishment in 1989 at all three locations was made easy owing to the cooperation of the weather. Planted while temperatures were low and shortly thereafter accompanied by adequate rainfall, the trees had no trouble withstanding the shock that accompanies newly planted saplings. Precipitation was adequate and evenly distributed over the entire growing season. This factor negated the need for irrigation and undoubtedly played a major role in assisting the tree through dormancy in the 1989-90 fall and winter. In fact, mortality was unexpectedly low in the 2nd year of the experiment, where only 7% of all trees perished.This adequate rainfall did not persist into the 2nd growing season and it became necessary to irrigate in 1990. Mortality also increased in the 3rd year (1991) to 10%.
The end of this three year endeavour marks the beginning of some hypothesis presented and prepared for at the onset. The most striking of these observations was tree location. Chosen because of side branching habit and vertical growth; those trees exhibiting these characteristics were spaced to allow those with more divergent or horizontal branching room to develop and no "crowding" is occurring. Pruning techniques will need to be employed to ensure this branching habit continues.
While proving to be an effective use of land the narrow row intercropping system (16') rapidly became a grove or plantation (thereby quickly losing the intercropping ideal) in the three year period. At the landowners request limited or no between tree row activity will be conducted in 1992. Vigorous growth and prolific tree branching created a problem at harvest in 1991 and it became a labour intensive operation as many hands were required to clear a path for the plot harvester. The combination of deep rich soils, superior tree stock and a weed free environment all contributed to the excellent growth at this site.
The wide row intercropping locations will remain in cash crop rotation for at least one more year before scaling down in size. This scaling down will imply only one pass of cropping operations rather than two as is presently the practice. It is believed this one pass system can be carried out for another four or five years before side branching restricts or eliminates inter tree row cropping.
None of the tree species planted at any location bore fruit in three years of observations. Flowers did develop on a number of hazelberts and chestnuts but all gave rise to either no fruit or fruit that did not fill. Many flowers were observed in the fall of 1991 on the hazelbert trees.
Seedling Triall - In May of the first year of this experiment seven hundred and twenty (720) seedlings were planted. In October of that same first year only 438 seedlings remained. This indicated a 39% mortality figure for all seedlings in Range 2. This can be broken down to further reveal individual species survival of the two stock types. Red Pine container stock exhibited a 39% mortality while its bare root counterpart showed only 13% mortality. Conversely for White Pine container stock 29% vs. 37% mortality for bare root. Norway Spruce revealed itself as a species requiring attention where 72% mortality was exhibited, in the container stock plots and 38% mortality in the bare root plots.
Striking discrepancies occur, however, when comparing seedlings planted into bare soil versus untilled, or pasture type conditions, where no soil tillage or herbicide applications were carried out. This procedure (planting into untilled, untreated areas) is common to many plantings throughout Southwestern Ontario and the results this experiment reveal are not inconsistent with what is apparent in many of these plantings that high mortality is experienced when planting seedlings into unprepared soil. The relatively high mortality rate of 65% for all species all stock types in the untilled when compared to the tilled, 16%, reveals this. Further breakdown showed even higher mortality rates for container when compared with bare root stock, for all species. (55% mortality bare root stock untilled versus 9% mortality of the same stock in the tilled area and similarly for containerized stock untilled 76% and tilled 18%). All this mortality, even when the seedlings were irrigated.
It is not unusual to expect a high percentage of mortality in newly planted seedlings whether containerized or bare root, but when irrigation attempts are carried out and mortality still remains higher than other factors causing this mortality must be questioned.
In comparing first year to second year survival rates, it is somewhat comforting to see the percentages show no appreciable increase or decrease (61% survival - 1988, 57% survival - 1989, 85% survival - 1990). In comparing absolute numbers of trees dying it is even more comforting to see a marked decrease in these numbers (282 - 1988, 190 - 1989, 39 - 1990). This is to say those trees surviving the first established year stand a better chance of surviving succeeding years.
Those trees planted on Range 3 performed in their initial year in a manner similar to seedlings in Range 2.