Temporal changes in forest floor carbon stocks following scarification in boreal lichen woodlands

Figures & data

Figure 1. Schematic representation of microsite types that are encountered in a sampling transect. Abbreviations for microsite types: ridge (RID); furrow (FUR); between furrows pair (BFP); and between skidder trails (BST).

Figure 2. Geographical location of the experimental sites in the Quebec’s managed boreal forest, Canada.

Table 1. Mean forest floor cover percentages and their respective standard deviations for each microsite type in the sampled sites

	BST	BFP	RID	FUR
Field coverage (%)	37.6	27.8	13.9	20.7
Standard deviation (%)	±13.3	±7.4	±6.6	±5.7

BST = between skidder trails, BFP = between furrows pair, RID = ridges, FUR = furrows.

Figure 3. Total C density by microsite type and time-since-scarification of the LW floor. Letters indicate a time-wise main effect multiple comparison between microsites. Refer to Figure 1 for microsite type abbreviations.

Table 2. Fixed effects of the ANOVAs of time from scarification and type of microsite on total carbon density (CD_TOT), and time from scarification and scarification treatment on total carbon stock (C_TOT).

Dependent variable	$R^2$	Factor	ndf	ddf	F ratio	P
CDTOT	0.88	$\mathrm{Time}$	3	7.0	8.4261	0.0101
		${\mu }_{\mathrm{site}}$	4	229.3	286.5833	< 0.0001
		$\mathrm{Time}\times {\mu }_{\mathrm{site}}$	12	229.3	21.8734	< 0.0001
$\log (C_{\mathrm{TOT}})$	0.80	$\mathrm{Time}$	3	7.0	3.1248	0.0968
		Scar	1	90.37	0.2217	0.6389
		$\mathrm{Time}\times \mathrm{Scar}$	3	90.49	1.3483	0.2638

Bold indicates significace (P < 0.05), ndf = numerator degrees of freedom, ddf = denominator degrees of freedom, µ_site = microsite.

Figure 4. Standardized C stocks by treatment and time-since-scarification of (a) living biomass (BIOM), (b) dead organic matter (DOM) and (c) total floor. Letters indicate a microsite-wise main effect multiple comparison between time steps. Refer to Figure 1 for microsite type abbreviations.

Figure 5. Total standardized C density by microsite types and time-since-scarification of the LW floor. Letters indicate a time-wise main effect multiple comparison between microsites. Refer to Figure 1 for microsite type abbreviations.

Table 3. Fixed effects of the ANOVAs of time from scarification and microsite on standard carbon stocks in the biomass pool (BIOM) and the humus pool (DOM). The tests on combined pools stocks and density (TOT) are also shown.

Dependent variable	$R^2$	Factor	Ndf	ddf	F ratio	P
$\log (C_{\mathrm{BIOM},\mathrm{std}}+1)$	0.77	Time	3	6	2.51	0.1555
		${\mu }_{\mathrm{site}}$	3	178	139.16	< 0.0001
		$\mathrm{Time}\times {\mu }_{\mathrm{site}}$	9	178	2.86	0.0036
$\log (C_{\mathrm{DOM},\mathrm{std}}+1)$	0.89	Time	3	6	0.84	0.5213
		${\mu }_{\mathrm{site}}$	3	178	388.06	< 0.0001
		$\mathrm{Time}\times {\mu }_{\mathrm{site}}$	9	178	18.87	< 0.0001
$\log C_{\mathrm{TOT},\mathrm{std}}$	0.89	$\mathrm{Time}$	3	6	1.95	0.2228
		${\mu }_{\mathrm{site}}$	3	178	350.92	< 0.0001
		$\mathrm{Time}\times {\mu }_{\mathrm{site}}$	9	178	22.11	< 0.0001
$\log C{D}_{\mathrm{TOT},\mathrm{std}}$	0.87	$\mathrm{Time}$	3	6	1.95	0.2228
		${\mu }_{\mathrm{site}}$	3	178	283.38	< 0.0001
		$\mathrm{Time}\times {\mu }_{\mathrm{site}}$	9	178	22.11	< 0.0001

Bold indicates significace (P < 0.05), ndf = numerator degrees of freedom, ddf = denominator degrees of freedom.,µ_site = microsite.

Table 4. Mean carbon density (CD) ratios and deltas by time from scarification and microsite type. Number in bold character indicates a significant (P < 0.05) one-tailed Student test on no departure from a reference value, which is: 1 for ratios, 0 for deltas, 50.62 for overall standard stocks and the latter weighted by the respective mean coverage proportions (respectively: 14.07, 19.03, 10.48 and 7.04).

		By years from scarification				By microsite
	Overall	3	8	12	18	BFP	BST	FUR	RID
CD ratio (CD/CDctrl)	0.85	1.08	0.77	0.87	0.84	0.98	1.07	0.35	1.59
Cstd (Mg ha^−1)	49.00	54.04	47.99	48.77	48.42	13.66	20.32	3.79	11.22
C delta (Mg ha^−1) (C – Cctrl)	−2.77	2.96	−4.07	−1.80	−4.35	−0.83	0.41	−6.61	4.26