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: Cistus ladanifer L. (Cistaceae) occupies extensive areas as a dominant species (shrublands) or is associated to other major forest typologies in the Iberian Peninsula. Cistus ladanifer shrublands are mostly present in oligotrophic lands with little valorisation and management and as they develop over the years (up to 20-years-old) they promote the ignition and perpetuation of fire. To contribute to the proper management and valorisation of such systems, a 5-year-old dense shrubland was evaluated for its labdanum resin, seeds, and biomass productivity using different non-destructive harvest periodicities (annual and biennial) and seasons (early, mid-, and late summer), in a two-year case-study. Annual harvest modality maximized labdanum resin productivity (reaching 230 ± 50 kg·ha−1 ·2 years−1 at late summer) and photosynthetic biomass productivity. In contrast, a biennial harvest yielded significant amounts of more diversified products. It maximized seeds productivity (reaching 75 ± 41 kg·ha−1 ·2 years−1 independently of the summer season) and lignified biomass. However, it also reached a labdanum resin productivity of 134 ± 20 kg·ha−1 ·2 yearrs−1 at late summer and a photosynthetic biomass productivity around two times lower than the annual harvest. In this study, we propose two modalities of periodic harvest to be considered as proper long cycle management practices of rockrose lands. It intends to minimize fire risks, break the vegetation auto-succession mechanism, and increase profit from nonproductive lands based on three direct outputs with a myriad of applications and valorisation pathways.

Cistus ladanifer L. (Cistaceae) is an endemic and abundant resource in the Iberian Peninsula and North Africa. This plant exudes an aromatic resin nowadays valued in the perfumery and fragrance industry. Traditional processes for the extraction and isolation of such resin use boiling water or alkaline water followed by acidic precipitation. However, a concern arises about the effluents resulting from these extraction processes. To overcome this concern, labdanum resin was extracted with Na2CO3 solution (25 g/L) at 60 oC and precipitated with sulphuric acid (5 M). The residual water was evaluated regarding total phenolic content, suspended solids, electric conductivity, and sulphate, sodium, magnesium, and calcium content. The effluent was characterized by a total phenolic content of 1245 ± 455 mgGAeq/L, 1338 ± 101 mg/L of suspended solids, pH of approximately 2, electric conductivity of 34.8 ± 0.7 mS/cm, 22284 ± 710 mg/L of sulphate, 9696 ± 1072 mg/L of sodium, 3.97 ± 0.24 mg/L of magnesium, 3.52 ± 0.80 mg/L of calcium, and a Sodium Adsorption Ratio of 876 ± 112. Because the values were far from the limit values set by Portugal decree-law 236/98 for residual waters discharged and irrigation waters, it was concluded that efforts should be made to optimize the extraction process. In that regard, a factorial designed experiment was done to evaluate the effect of Na2CO3 concentration (0; 2.5; and 25 g/L), extraction temperature (60 and 100 oC) and acidification extent (pH 2, neutralization, and no acidification) on the residual water quality and on the yield of labdanum resin extraction. Alkalinization and acidification are important to obtain high resin extraction yields (Andalusian vs. Zamorean process), but mostly alkalinization may be reduced to meet sulphate criteria for discharge without significantly affecting resin extraction yields. Despite that, to meet salinity criteria for irrigation waters a higher reduction in alkalinization is needed for Andalusian processes. Phenolic content, although lower for extractions done at 60 oC, was far from the limit values for discharge, regardless experimental conditions. Given the high phenolic content the residual water from labdanum extraction by both traditional processes must be treated before discharge. If separated, phenolic compounds may be valorized as a by-product.