The observation of phenological events can be used as biological indicator of environmental changes, especially from the perspective of climate change. In boreal forests, the onset of the bud burst is a key factor in the length of the growing season. With current climate change, the major factors limiting the growth of boreal trees (i.e., temperature and nitrogen availability) are changing and studies on mature trees are limited. The aim of this study was to investigate the effects of soil warming and increased nitrogen ( 3

Since the late 1950's, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Malaysian palm oil in particular had steeply increased since the mid-1970s and by 2013, the commodity was the leading foreign exchange earner. To fulfill and sustain this demand, the country's economy has steadily shifted bias towards production and associated value addition of palm oil products for export. However, as a consequence, many of Malaysia's natural tropical forests have been converted to palm oil farming resulting in loss of approximately 10,000 km² of forest cover over the past twenty-five years, and biodiversity has been displaced or lost. To provide a deeper insight into the interplay amongst key interrelated environmental and socio-economic variables, and a forecast of possible future balance, we used a systems dynamism modeling tool, STELLA R (structural thinking, experiential learning laboratory with animation), to simulate and project how Malaysia could achieve a medium-term sustainable balance or optimization between palm oil production and forest conservation without compromising on human social welfare. The model consisted of four main modules (environmental, economic, social development and human welfare) each with component parameters, and interconnected by input and output loops. Model calibrations, testing and pre-runs involved existing official 30-year time-series datasets. Subsequently, four scenarios: Environmental conservation; Economic growth under increased global palm oil demand; Economy decline under decreased palm oil demand; and Control condition with little or no change, were selected for simulated projections of future possibilities. Simulation results showed that scenarios and variable interactions that reduce environmental N. E. Otieno et al. 56damage would offer the best chance for optimizing the palm oil economy while also minimizing forest loss and promoting citizen social welfare.

Climate change is projected to intensify the global hydrological cycle and increase temperatures. Excess N deposition could limit plant productivity because of a lack of plant–soil system efficiency with reduced water availability. However, the effects of soil warming and N‐addition on tree water transport and water use remain poorly understood. This study aimed to quantify the effects of soil warming and N‐addition associated with meteorological variables on the sap flux density and stem radius variation in black spruce (Picea mariana [Mill.] B.S.P.). From 2008 to 2014, we conducted a long‐term experiment on mature trees growing in two stands (Bernatchez [BER] and Simoncouche [SIM]) at different latitudes to evaluate the effect of soil warming (H) and N‐addition. During 2014, we investigated soil and plant water status between May and August, sap flux density from July to August and stem radius variation over the whole year. At the colder, northern site (BER), we detected a significant increase in sap flux density with the H‐treatment, whereas no effect was observed at the warmer, southern site (SIM). At BER, diurnal sap flux density in H × N‐addition treatment showed a significant effect in the afternoon near the peak of day compared with the other treatments. We found no significant effects of independent single or combined factors on soil and plant water status and stem radius variation at either site. Under climate change, black spruce at more northern sites could have a better water use and storage for wood productivity than those at more southern sites.