Plant ecologists have long been interested in the effects of fire on vegetation. Thermocouples have been in their proverbial toolbox for decades, despite temperature not being a direct product or measure of wildland fire behaviour or fire effects. To better represent the cumulative impact of high-temperature exposure on organisms, ecologists often use temperature–time curves from thermocouples to calculate residence time—the duration of heat exposure above a threshold temperature—which can be used to calculate another popular metric, degree \(\cdot \)seconds. A systematic literature review of 105 published papers shows that residence time, especially, and degree \(\cdot \) seconds are common metrics derived from raw temperature–time data. While several errors in thermocouple readings have been previously identified and addressed—responsiveness to heating, discrepancy between thermocouple temperature and actual temperature of the medium surrounding the thermocouple—this paper highlights a previously unconsidered source of error that must be reconciled for metrics like residence time to be biologically valid: the disproportionately long time it takes for thermocouples to cool once heat input is complete. Using an array of thermocouples in a fume hood over a Bunsen burner before and after the flame is extinguished, this paper shows that after being exposed to flame, 30-gauge K-type thermocouples require 80–100 s to register ambient temperatures despite taking only about 5 s to respond to heating. The review indicates ecologists give no consideration for this disproportionately slow cooling response. These findings indicate that residence time (and therefore degree \(\cdot \) seconds) have been over-estimated in the fire ecology literature. The proposed solution is to simply truncate temperature–time curves at the point temperature begins to decline, which indicates a shift from the biologically relevant effect of heat input to the biologically irrelevant, physical properties (heat diffusivity) of the thermocouple itself. Conceptual models present these biologically relevant portions of the temperature–time curve and identify parts of the biologically relevant curve that might be useful in quantifying components of flammability.

植物生态学家对火对植被的影响一直很感兴趣。尽管温度不是野火行为或火灾影响的直接产物或量度，但热电偶已在其众所周知的工具箱中使用了数十年。为了更好地表示在生物体高温暴露的累积影响，生态学家经常使用的温度-时间曲线，从热电偶计算停留时间的热暴露的持续时间-the高于阈值温度，其可以被用来计算另一种流行的度量，度 \ （\ cdot \）秒。对105篇发表的论文进行系统的文献综述表明，停留时间特别是和程度（\ cdot \）秒是从原始温度时间数据得出的通用指标。尽管先前已经确定并解决了热电偶读数中的几个错误（对加热的响应，热电偶温度与热电偶周围介质的实际温度之间的差异），但本文着重指出了以前未考虑的错误源，必须将其调和为停留时间等度量标准。具有生物学上的有效性：完成热量输入后，热电偶冷却所花费的时间过长。在熄灭火焰之前和之后，在本生灯上的通风橱中使用一系列热电偶，火焰暴露后，30规格的K型热电偶需要80–100 s来记录环境温度，尽管仅采取了这种措施。约5秒钟即可响应加热。审查表明，生态学家没有考虑这种不成比例的缓慢冷却反应。这些发现表明，停留时间（因此是学位）在火灾生态学文献中高估了\（\ cdot \）秒。提出的解决方案是简单地截断温度开始下降时的温度-时间曲线，这表明从热输入的生物学相关影响向热电偶本身的生物学无关的物理性质（热扩散率）转变。概念模型显示了温度-时间曲线的这些生物学相关部分，并确定了生物学相关曲线的某些部分，这些部分可能有助于量化可燃性成分。