Patterns and causes of temporal variation in tree seed production

树种的受精行为(定义为种子作物在空间上的同步和时间上的间歇性生产)在生态学中具有极其重要的意义(例如，鹿和啮齿动物的显著营养效应；食性鸟类种群的爆发；风媒物种的花粉流动等)。这在林业中也是相当重要的--桅杆活动的不可预测性有利于更昂贵但更可靠的种植再生选择。到目前为止，人们可能做出的唯一一致的声明是，盛年是地区性存在的，年际花粉和胚珠的产生密切相关，一个地区内的大多数物种彼此不同步，天气无疑起着重要作用(产生芽分化的资源和/或线索)。这项拟议的研究有一系列目标，包括对全球范围内对马尾松对纬度、海拔、经度和生活史特征的依赖程度的考察，如气生种子库和一些松树物种的强制鸟类扩散。我将把我正在进行的数据集从6年延长到11年，在从科罗拉多州到北冰洋(因努维克)以及从阿拉斯加内陆到纽芬兰的同一68个林分中，测量青云杉(白云杉)和非常接近的英格尔曼尼云杉(英格尔曼云杉)的每一断面积的卵球；然后我将使用这些数据来测试基于资源、基于线索或资源和线索的组合的繁殖模型。此外，我将在艾伯塔省西部、马尼托巴省中部和魁北克西北部的年轻白云杉林中进行一系列实验，通过在正常年份诱导水分胁迫、在非常干旱的年份灌溉、在盛年移除未成熟的雌性球果以及在盛年安装人工球果簇来模拟真实球果的阴影，来比较资源和天气信号在控制年度繁殖产量方面的效果。最后，我将把北方森林四个空间独立区域的每一断面积和烧毁面积联系起来，以确定大火年份之后是否通常会有肥大作物。

Masting behavior (defined as the spatially synchronous and temporally episodic production of seed crops) in tree species is of tremendous importance in ecology (e.g. dramatic trophic effects for deer and rodents; eruptions of granivorous bird populations; pollen flux in anemophilous species; etc). It is also quite important in forestry-the unpredictable nature of masting events has favored the more expensive but more reliable regeneration option of planting. As of now the only consensual statements one might make are that a mast year is of regional extant with inter-annual pollen and ovule production closely linked, most species within a region are not synchronized with one another, and weather undoubtedly plays a major role (generating resources and/or cues for bud differentiation). The proposed study has a number of objectives including a global examination of the dependence on masting on latitude, altitude, longitude, and life history traits such as aerial seedbanks and obligate bird dispersal of some Pine species. I will extend my on-going data set from 6 to 11 years, measuring ovulate cones per basal area of Picea glauca (white spruce) and the very close-related P. engelmannii (Engelmann spruce) in the same 68 stands from Colorado to the Arctic Ocean (Inuvik), and from interior Alaska to Newfoundland; and then I will use these data to test models of reproduction that are resource-based, cue-based, or a combination of resource and cue. Further, I will compare the effect of resources vs weather cues in governing annual reproductive output in a series of experiments in young white spruce stands in western Alberta, central Manitoba, and northwest Quebec by inducing water stress during normal years, irrigation during very dry years, removal of immature female cones during mast years, and installation of artificial clusters of cones to imitate the shading of real cones during mast years. Finally, I will relate cones per basal area and area burned in four spatially independent regions of the boreal forest to ascertain if big fire years are typically followed by mast crops.