The effect of tree age, daily sap volume and date of sap collection on the content of minerals and heavy metals in silver birch (Betula pendula Roth) tree sap

Abstract

The aim of this study was to determine the effect of the age of trees, daily sap volume as well as the term of tapping birch sap collected in the forest environment on the content of selected minerals (zinc, copper and manganese) and heavy metals (lead, nickel, chromium and cadmium). The study was performed on material taken from two stands (aged 34 and 84 years) in a moist broadleaved forest habitat with a dominant share of silver birch (Betula pendula Roth). The research results confirmed the presence of both nutritional essential minerals and hazardous heavy metals in the birch sap. At the same time, the content of minerals and heavy metals was found to be very variable and the differences between their concentrations, recorded on the same day of collecting in several trees of the same age group, can be even several dozen times higher. Depending on the examined elements, the factors influencing their content vary. The age of the trees determines only the manganese content; daily sap volume significantly affects the content of manganese and copper, and date of collection differentiates the content of zinc, lead, nickel and cadmium. The results may be interesting in the context of developing procedures for collecting birch sap for the purpose of obtaining raw material with beneficial nutritional values and a high level of health safety. For this reason, our recommendation for guaranteeing the health safety and high nutritional value of birch sap is to combine batches of raw material taken from as many trees as possible, and at the same time to publicize the fact that collecting birch sap from just one single tree may result in a raw material that is both dangerous and has no nutritional benefits.

Antioxidant activities in relation to the transport of heavy metals from the soil to different parts of Betula pendula (Roth.)

“…This makes it possible to use birch as a monitoring plant and focus on the leaves as the largest accumulators, as the authors emphasise, of zinc and sometimes cadmium. Hence, most research on birch focuses on the issue of the content of heavy metals in leaves or in the roots [ 8 , 10 , 16 , 17 , 62 , 64 – 72 ], and increasingly also sap [ 29 , 73 – 76 ]. It is worth paying attention to the other uses of birch.…”

Qualitative Changes in Birch Sap after Freezing and Thawing

“…Pathogenic microorganisms E. coli and Salmonella were not detected in the thawed sap at various depths, while molds were found in amounts of <1 log CFU/mL. Birch sap is an ideal medium for microorganisms because it contains enough available organic compounds and mineral substances, so the sap ferments rather quickly [10,20]. It was determined that in the upper part of the container (where the depth of the thawed sap was 10-30% the depth of the sap in the container) the total amount of microorganisms was even lower than that in fresh birch sap, at 1.27 log colony-forming units (CFU) per milliliter and 1.60 log CFU/mL, respectively.…”

“…Harvesting and processing birch sap is a delicate and precise procedure that requires a careful understanding of the birch tree's biology and the optimal time to tap into its sap. Researchers have found that the chemical composition of birch sap depends on the type of birch habitat [8,9], the age of the birch tree, the daily sap volume, and the date of sap collection [10]. Typically, sap is harvested in early spring when the sap begins to rise and before the buds open.…”

Modeling and Assessing the Spatial and Vertical Distributions of Potentially Toxic Elements in Soil and How the Concentrations Differ

“…The effect of Cr is not only recorded in food crops but also in forest trees. The health of forest plants has been at risk because of exacerbated Cr content in the soil [ 37 ]. Globally, there have been reports on the effects of increased Cu, Fe, Mn, Mo, Zn, Ni, and other PTEs on soils, plants, animals, humans, and water.…”