Foliar analysis and response of fertilized chlorotic western hemlock and western red cedar reproduction on salal-dominated cedar–hemlock cutovers on Vancouver Island
Microplot and conventional plot trials were used to determine the nutritional status and required nutrient additions to bring young regenerations of western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western red cedar (Thujaplicata Donn ex D. Don) out of "check." The trees were growing on deep mor-humus Podzols invaded by dense salal (Gaultheriashallon). Salal removal by grubbing and application of Garlon was also tested. Foliar vector analysis, used for hemlock, identified a response to N and P that was confirmed by subsequent 3-year height growth response. Salal removal resulted in increased N uptake only in cedar. Cedar also responded to N and P additions, but vector analysis was not feasible owing to indeterminate growth. Foliar analysis values are compared with published data. It is suggested that salal competition or allelopathy may be the primary cause of inadequate N and P nutrition.