Digital photogrammetry was used to measure growth rates and track changes at the margins of marked Rhizocarpon geographicum agg. thalli on quartzite at the Illecillewaet Glacier in western Canada. The decadal rates were used to validate a lichenometric “growth curve” calibrated using the five largest thalli on historically and tree-ring dated surfaces. Macro-photographs of lichens were orthocorrected by ‘Structure from Motion’ (SfM) techniques to create a 20 yr image timeline. Model resolution was high (0.01 to 0.03 mm pix), photo alignment was accurate (mean relative error < 1.4%) and measurements were validated. Mean areal growth in 59 thalli was highly variable ($\overline{x}$ = 9.43 mm² yr⁻¹ for 1996–2006; and 7.72 mm² yr⁻¹ for 2006–2016). Tiny thalli (<5 mm long axis) had jagged outlines and slow irregular growth (0 to 0.2 mm yr⁻¹). Long axis growth in the five fastest of 45 thalli (>5 mm long axis) with circular outlines was 0.5 to 0.92 mm yr⁻¹ and mean annual radial growth on four radii per thallus was 0.23 to 0.31 mm yr⁻¹. Several thalli kept a nearly circular shape even after fusing with others. Extrapolated mean radial growth of the fastest thallus in either decade closely predicted the largest and five thallus sizes on historically dated surfaces (−5.43 mm difference at 53 yr, <1.75 mm at 75 to 101 yr). This is an error of about one year at 75 to 101 yr. The findings validate indirectly calibrated rates and surface ages at this site and challenge key assumptions and claims made by proponents of lichenometric dating.

数字摄影测量法用于测量生长速度并跟踪标记的Rhizocarpon geoum agg边缘的变化。加拿大西部Illecillewaet冰川的石英岩上的塔利岩。十年率用于验证使用历史上和树木年轮过时的表面上的五个最大的塔利校准的地衣测量法“生长曲线”。地衣的宏观照片通过“运动结构”（SfM）技术进行了矫正，以创建20年图像时间轴。模型分辨率高（0.01至0.03 mm像素像素），照片对准准确（平均相对误差<1.4％），并且测量结果得到验证。59thalli的平均面积增长变化很大（$\overline{X}$ = 1996-2006 年为9.43毫米²年^-1；和2006-2016 年的7.72毫米²年^-1）。微小的thalli（长轴<5 mm）具有锯齿状的轮廓和缓慢的不规则生长（0至0.2 mm yr ^-1）。具有圆形轮廓的45个塔利（> 5 mm长轴）中速度最快的五个中的长轴生长为0.5到0.92 mm yr ^-1，每个th的四个半径上的年平均径向生长为0.23到0.31 mm yr ^-1。即使与其他人融合后，也有数个塔利（thalli）保持接近圆形的形状。在这两个十年中，最快的all的外推平均放射状生长均密切预测了有历史日期的表面上最大和五个th的大小（53年时相差5.43毫米，75至101年时相差1.75毫米）。在75到101年间，这大约是一年的误差。这些发现间接验证了该地点的校准率和地表年龄，并挑战了地衣计量学支持者提出的主要假设和主张。