Prescribed fires are an important management tool for reducing fuels and returning fire to the landscape. However, rarely are changes in fuels fully quantified using pre- to post-prescribed fire measurements, and those studies that do exist show variable results. In the southern Rockies, little literature exists on the impacts of prescribed fires, thus we examined multiple prescribed fires in northern Colorado to understand fire effects and changes in fuel complexes. Most prominently, prescribed fires influenced litter, duff, and rotten coarse woody debris but did not influence other surface fuels. Crown base height increased and tree density decreased, while basal area was relatively unimpacted. Season of burning impacted fire effects as substrate burn severity, bole char, and crown volume scorched were highest in summer and fall. Continued monitoring of prescribed fires is critical to understand the influence of prescribed fire on wildfires and ultimately improving prescribed fire outcomes.

All data were collected by Colorado Forest Restoration Institute field crews between 2017–2021 using protocols available here: https://cfri.colostate.edu/publication/. 

Plots were randomly located across each site. PreRX is used for data collected before prescribed fire, RX is used for data collected within 1–2 months of 
prescribed fire, and PostRX is used for data collected 1–2 years after prescribed fire. Data collected during the RX visit is limited to fine woody fuel,
ground fuel, burn severity, and post-fire tree measurements. Fire severity measurements (RX) were recorded only in burned plots. Treatment Unit denotes 
different prescribed fire sites, with the exception of BSR-1C2 and BSR-2T4 being sub-units within the same site. 

• BurnSeason: This worksheet contains the season and year of burn for each plot that experienced prescribed fire.
• Plots: This table includes plot locations, date of each data collection visit, and whether the plot area experienced fire.
• Trees: A 10 BAF prism was used to measure trees with a DBH ≥ 12.7 cm. Saplings (trees < 12.7cm DBH and ≥ 1.37m height) were measured in a 0.004ha fixed 
  radius plot. Tree and sapling measurements include diameter at breast height (inches), tree height (feet), tree species (USDA plant code), and tree status (live/dead). 
  At 2 of the 3 sites crown base height (CBH, lowest height of continuous live vegetation in feet) is included. When no trees were present at a plot, Species is 
  recorded as NONE.
• FineWoodyFuel: Surface fine woody debris (diameter < 7.62 cm) were collected in 1 m² quadrats using the photoload sampling technique (Keane and Dickinson 2006). 
  Fine woody loading estimates were calibrated with a regression equation developed locally to generate more accurate estimates (Morici and Cannon 2019).
• CoarseWoodyFuel: For surface coarse woody debris (diameter ≥7.62 cm), we recorded two end diameters (inches), length (feet), and decay status (rotten/sound) 
  for each piece of wood within a fixed radius plot. Depending on initial plot installation dates, the fixed radius plot for coarse woody debris was between 
  0.04 ha and 0.004 ha.
• Ground fuel: Litter and Duff depths (inches) were collected at 12 standard locations within each plot.
• BurnSeverity: Fire severity and effects measurements were taken 0–2 months following prescribed fire. Within each plot, fire effects on the forest floor were classified 
  for 10–12 subplots (Fire Monitoring Handbook 1965).
• PostRXtrees: Fire severity and effects measurements were taken 0–2 months post-prescribed fire. For each tree, we recorded an ocular estimate of percent crown volume scorch, or the percentage of needles that are visibly red or black after the fire, and measured char height (feet) as the highest burn mark on a tree bole. 

Microsoft Excel