Forest Root Growth Dynamics

Forest-scale root growth dynamics

Water limitation is the most limiting factor in forest tree growth. With predicted higher frequency and severity of drought, species differences in water use strategies and drought vulnerability may lead to shifts in forest species composition. Growing evidence suggests that belowground interactions are crucial to plant growth success yet they remain poorly understood, especially during drought. Using minirhizotron imaging, the aim of this study is to investigate changes in root dynamics and species interactions of beech and spruce trees with contrasting drought stress strategies under seasonal water limitation in a unique experimental forest site near Munich in Germany. The distinctive tree layout and technical setup allow for the testing of novel hypotheses that cannot be examined at other sites.

3D imaging of interacting and individual root systems

Research in the field of plant biology has recently demonstrated that interactions among self- and non-self roots can dramatically alter root growth. As 3D imaging technologies become more widely available, questions about the occupation and exploration of space by interacting root systems can be better addressed, offering new insights to this important yet problematic component of root growth dynamics. Our research employed micro-CT to capture the spatial distribution of both interacting and individual root systems. From 3D reconstructions based on CT image data, we extracted traditional belowground metrics such as root length, surface area, volume, and root tip counts.  Moreover, we also developed a series of belowground metrics that took advantage of the full 3D information, and quantified spatial relationships among root tips and root volume: a data set inaccessible with a 2D approach.

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Figure: CT analysis and 3D visualization  of root system