Ecophysiological interpretation of the mechanisms and dynamics of sap production in sugar maple

糖枫是加拿大经济的关键物种，在林业、旅游业、食品和农业中发挥着重要作用。在当前全球变暖的情况下，该物种及其主要产品枫糖浆正受到不断变化的环境条件的巨大压力。现在迫切需要预测这些变化，调整南方地区的树液提取生产系统，并利用北方地区的新发展机会。我提出了创新的长期监测，使用自动传感器自动收集的生理和天气数据，并在高时间分辨率的糖枫树树液生产。我的建议旨在开发和测试第一个描述sap流动和生产的机械模型。特别是，我（1）描述的树液流的昼夜节律周期和变化的干;（2）确定与树液的高生产力的解剖和生理特征;（3）量化的影响，天气的动态和量的树液在春季生产;和（4）联合收割机所有的经验观察，建立第一个理论模型，描述的机制，树液生产糖枫树。从2017年开始运行的一个永久性地块开始，我想在糖枫范围内的其他永久性地块上配备测树仪和液流探针，以便在休眠结束时每30分钟监测一次春季茎的生理状况。树液的产生可以用连接到糖枫树上的雨量计自动测量。芽的萌发和叶片的生长是由phenocam以每日分辨率检测的，即使用安装在田间的数码相机收集的数字图像。所有传感器都由气象站的数据记录器激活，收集环境和土壤湿度条件。该模型将被用来预测变化的条件对茎的再水化和春季生长的再激活及其后果的时间和持续时间的汁液生产的影响。研究结果将有助于理解和量化树液流动和春季树液生产的过程，并量化气候变化对制糖季节的影响。本项目将建议在树液收获期间调整生产系统。更广泛地说，它将支持生产者维持南方人口生产力的战略，并增加对北方糖枫林的开发。

Sugar maple is a key species in Canada's economy, playing an important role in forestry, tourism, food and agriculture. Under the current global warming, this species and its main product, maple syrup, are experiencing a significant pressure by the changing environmental conditions. It is now urgent to anticipate these changes, adapt the productive system of sap extraction in the Southern regions, and take advantage of new development opportunities for the Northern regions. I propose innovative long-term monitoring using automatic sensors for the automatic collection of physiological and weather data, and sap production in sugar maple at high temporal resolution. My proposal aims to develop and test the first mechanistic model describing flow and production of sap. In particular, I (1) describe the circadian cycles of sap flow and variation in the stem; (2) determine the anatomical and physiological traits associated with a high productivity of sap; (3) quantify the impact of weather on the dynamics and amount of sap produced in spring; and (4) combine all empirical observations to build a first theoretical model describing the mechanisms of sap production in sugar maple. Starting with one permanent plot already running since 2017, I would like to equip other permanent plots across the sugar maple range with dendrometers and sap flow probes to monitor each 30 min the physiological conditions of stems in spring, at the end of dormancy. Sap production can be measured automatically using rain gauges connected to tapping sugar maples. Bud break and leafing are detected at a daily resolution by phenocam, i.e. using digital images collected by digital cameras installed in the field. All sensors are activated by dataloggers of a weather station collecting environmental and soil moisture conditions. The model will be used to predict the effects of changing conditions on stem rehydration and spring growth reactivation and their consequences on the timings and duration of sap production. The results will help to understand and quantify the processes underlying sap flow and spring sap production, and quantify how the sugar season will be affected by the climate change. This project will suggest the adaptations of the production system during sap harvesting. More generally, it will support the strategies of producers to maintain the productivity of populations in the South, and increase the exploitation of sugar maple at the Northern stands.