Patterns and causes of temporal variation in tree seed production

树种的桅杆行为（定义为种子作物的空间同步和时间上的间歇性生产）在生态学中具有巨大的重要性（例如对鹿和啮齿动物的显著营养效应;食草鸟类种群的爆发;风媒物种的花粉通量等）。它在林业中也很重要桅杆事件的不可预测性有利于更昂贵但更可靠的再生选择种植。到目前为止，唯一一致同意的说法可能是，一个主年份是区域性的，年际花粉和胚珠生产密切相关，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（产生资源和/或芽分化的线索）。拟议中的研究有一些目标，包括一个全球性的检查桅杆纬度，海拔高度，经度和生活史特征，如空中种子库和专性鸟类传播的一些松树物种的依赖。我将把我正在进行的数据集从6年延长到11年，测量云杉每基面积的胚珠锥（白色云杉）和非常接近的P. engelmannii（Engelmann云杉）在同样的68站从科罗拉多到北冰洋（因纽维克），并从内陆阿拉斯加到纽芬兰;然后我会用这些数据来测试基于资源的、基于线索的、或资源和线索相结合的繁殖模型。此外，我将在阿尔伯塔西部、马尼托巴中部和魁北克西北部的年轻白色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、在肥大年份去除未成熟的雌性球果、并安装人工锥群，以模仿真实的锥的阴影。 最后，我将涉及锥每断面积和面积烧毁在四个空间上独立的地区的北方森林，以确定如果大火年通常是由桅杆作物。

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.